feat: Calendar Cache and Sync (#23876)

* feat: calendar cache and sync - wip * Add env.example * refactor on CalendarCacheEventService * remove test console.log * Fix type checks errors * chore: remove pt comment * add route.ts * chore: fix tests * Improve cache impl * chore: update recurring event id * chore: small improvements * calendar cache improvements * Fix remove dynamic imports * Add cleanup stale cache * Fix tests * add event update * type fixes * feat: add comprehensive tests for new calendar subscription API routes - Add tests for /api/cron/calendar-subscriptions-cleanup route (9 tests) - Add tests for /api/cron/calendar-subscriptions route (10 tests) - Add tests for /api/webhooks/calendar-subscription/[provider] route (11 tests) - Add missing feature flags for calendar-subscription-cache and calendar-subscription-sync - All 30 tests pass with comprehensive coverage of authentication, feature flags, error handling, and service instantiation Tests cover: - Authentication scenarios (API key validation, Bearer tokens, query parameters) - Feature flag combinations (cache/sync enabled/disabled states) - Success and error handling (including non-Error exceptions) - Service instantiation with proper dependency injection - Provider validation for webhook endpoints Co-Authored-By: Volnei Munhoz <volnei.munhoz@gmail.com> * feat: add comprehensive tests for calendar subscription services, repositories, and adapters - Add unit tests for CalendarSubscriptionService with subscription, webhook, and event processing - Add unit tests for CalendarCacheEventService with cache operations and cleanup - Add unit tests for CalendarSyncService with Cal.com event filtering and booking operations - Add unit tests for CalendarCacheEventRepository with CRUD operations - Add unit tests for SelectedCalendarRepository with calendar selection management - Add unit tests for GoogleCalendarSubscriptionAdapter with subscription and event fetching - Add unit tests for Office365CalendarSubscriptionAdapter with placeholder implementation - Add unit tests for AdaptersFactory with provider management and adapter creation - Fix lint issues by removing explicit 'any' type casting and unused variables - All tests follow Cal.com conventions using Vitest framework with proper mocking Co-Authored-By: Volnei Munhoz <volnei.munhoz@gmail.com> * fix: improve calendar-subscriptions-cleanup test performance by adding missing mocks - Add comprehensive mocks for defaultResponderForAppDir, logger, performance monitoring, and Sentry - Fix slow test execution (933ms -> <100ms) caused by missing dependency mocks - Ensure consistent test performance across different environments Co-Authored-By: Volnei Munhoz <volnei.munhoz@gmail.com> * Fix tests * Fix tests * type fix * Fix coderabbit comments * Fix types * Fix test * Update apps/web/app/api/cron/calendar-subscriptions/route.ts Co-authored-by: Alex van Andel <me@alexvanandel.com> * Fixes by first review * feat: add database migrations for calendar cache and sync fields - Add CalendarCacheEventStatus enum with confirmed, tentative, cancelled values - Add new fields to SelectedCalendar: channelId, channelKind, channelResourceId, channelResourceUri, channelExpiration, syncSubscribedAt, syncToken, syncedAt, syncErrorAt, syncErrorCount - Create CalendarCacheEvent table with foreign key to SelectedCalendar - Add necessary indexes and constraints for performance and data integrity Fixes database schema issues causing e2e test failures with 'column does not exist' errors. Co-Authored-By: Volnei Munhoz <volnei.munhoz@gmail.com> * only google-calendar for now * docs: add Calendar Cache and Sync feature documentation - Add comprehensive feature overview and motivation - Document feature flags with SQL examples - Include SQL examples for enabling features for users and teams - Reference technical documentation files Addresses PR #23876 documentation requirements Co-Authored-By: Volnei Munhoz <volnei.munhoz@gmail.com> * docs: update calendar subscription README with comprehensive documentation - Undo incorrect changes to main README.md - Update packages/features/calendar-subscription/README.md with: - Feature overview and motivation - Environment variables section - Complete feature flags documentation with SQL examples - SQL examples for enabling features for users and teams - Detailed architecture documentation Addresses PR #23876 documentation requirements Co-Authored-By: Volnei Munhoz <volnei.munhoz@gmail.com> * fix docs * Fix test to available calendars * Fix test to available calendars * add migration and sync boilerplate * fix typo * remove double log * sync boilerplate --------- Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com> Co-authored-by: Alex van Andel <me@alexvanandel.com> Co-authored-by: Keith Williams <keithwillcode@gmail.com>
2025-09-29 14:26:14 +00:00
parent 855a02091f
commit e6b2116a2b
42 changed files with 4723 additions and 42 deletions
@@ -144,6 +144,12 @@ GOOGLE_WEBHOOK_TOKEN=
 # Optional URL to override for tunelling webhooks. Defaults to NEXT_PUBLIC_WEBAPP_URL.
 GOOGLE_WEBHOOK_URL=

+# Token to verify incoming webhooks from Microsoft Calendar
+MICROSOFT_WEBHOOK_TOKEN=
+
+# Optional URL to override for tunelling webhooks. Defaults to NEXT_PUBLIC_WEBAPP_URL.
+MICROSOFT_WEBHOOK_URL=
+
 # Inbox to send user feedback
 SEND_FEEDBACK_EMAIL=

@@ -6,6 +6,7 @@ import { createMocks } from "node-mocks-http";
 import { describe, expect, test } from "vitest";

 import { HttpError } from "@calcom/lib/http-error";
+import type { User } from "@calcom/prisma/client";

 import handler from "../../../pages/api/selected-calendars/_post";

@@ -72,7 +73,7 @@ describe("POST /api/selected-calendars", () => {

      prismaMock.user.findFirstOrThrow.mockResolvedValue({
        id: 444444,
-      } as any);
+      } as User);

      prismaMock.selectedCalendar.create.mockResolvedValue({
        credentialId: 1,
@@ -95,6 +96,16 @@ describe("POST /api/selected-calendars", () => {
        unwatchAttempts: 0,
        createdAt: new Date(),
        updatedAt: new Date(),
+        channelId: null,
+        channelKind: null,
+        channelResourceId: null,
+        channelResourceUri: null,
+        channelExpiration: null,
+        syncSubscribedAt: null,
+        syncToken: null,
+        syncedAt: null,
+        syncErrorAt: null,
+        syncErrorCount: null,
      });

      await handler(req, res);
@@ -140,6 +151,16 @@ describe("POST /api/selected-calendars", () => {
        unwatchAttempts: 0,
        createdAt: new Date(),
        updatedAt: new Date(),
+        channelId: null,
+        channelKind: null,
+        channelResourceId: null,
+        channelResourceUri: null,
+        channelExpiration: null,
+        syncSubscribedAt: null,
+        syncToken: null,
+        syncedAt: null,
+        syncErrorAt: null,
+        syncErrorCount: null,
      });

      await handler(req, res);
@@ -0,0 +1,213 @@
+import { NextRequest } from "next/server";
+import { describe, test, expect, vi, beforeEach } from "vitest";
+
+import { CalendarCacheEventService } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventService";
+
+vi.mock("next/server", () => ({
+  NextRequest: class MockNextRequest {
+    url: string;
+    method: string;
+    nextUrl: { searchParams: URLSearchParams };
+    private _headers: Map<string, string>;
+
+    constructor(url: string, options: { method?: string } = {}) {
+      this.url = url;
+      this.method = options.method || "GET";
+      this._headers = new Map();
+      this.nextUrl = { searchParams: new URLSearchParams(url.split("?")[1] || "") };
+    }
+
+    headers = {
+      get: (key: string): string | null => this._headers.get(key.toLowerCase()) || null,
+      set: (key: string, value: string): void => {
+        this._headers.set(key.toLowerCase(), value);
+      },
+      has: (key: string): boolean => this._headers.has(key.toLowerCase()),
+    };
+  },
+  NextResponse: {
+    json: vi.fn((body, init) => ({
+      json: vi.fn().mockResolvedValue(body),
+      status: init?.status || 200,
+    })),
+  },
+}));
+
+vi.mock("@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventService");
+vi.mock("@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventRepository");
+vi.mock("@calcom/lib/logger", () => ({
+  default: {
+    getSubLogger: vi.fn(() => ({
+      info: vi.fn(),
+      error: vi.fn(),
+    })),
+  },
+}));
+vi.mock("@calcom/lib/server/perfObserver", () => ({
+  performance: {
+    mark: vi.fn(),
+    measure: vi.fn(),
+  },
+}));
+vi.mock("@sentry/nextjs", () => ({
+  wrapApiHandlerWithSentry: vi.fn((handler) => handler),
+  captureException: vi.fn(),
+}));
+vi.mock("@calcom/lib/server/getServerErrorFromUnknown", () => ({
+  getServerErrorFromUnknown: vi.fn((error) => ({
+    message: error instanceof Error ? error.message : "Unknown error",
+    statusCode: 500,
+    url: "test-url",
+    method: "GET",
+  })),
+}));
+vi.mock("../../defaultResponderForAppDir", () => ({
+  defaultResponderForAppDir: vi.fn((handler) => handler),
+}));
+vi.mock("@calcom/prisma", () => ({
+  prisma: {},
+}));
+
+const mockCalendarCacheEventService = vi.mocked(CalendarCacheEventService);
+
+describe("/api/cron/calendar-subscriptions-cleanup", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    vi.stubEnv("CRON_API_KEY", "test-cron-key");
+    vi.stubEnv("CRON_SECRET", "test-cron-secret");
+  });
+
+  describe("Authentication", () => {
+    test("should return 403 when no API key is provided", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions-cleanup");
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(403);
+      const body = await response.json();
+      expect(body.message).toBe("Forbidden");
+    });
+
+    test("should return 403 when invalid API key is provided", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions-cleanup");
+      request.headers.set("authorization", "invalid-key");
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(403);
+      const body = await response.json();
+      expect(body.message).toBe("Forbidden");
+    });
+
+    test("should accept CRON_API_KEY in authorization header", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions-cleanup");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockCleanupStaleCache = vi.fn().mockResolvedValue(undefined);
+      mockCalendarCacheEventService.prototype.cleanupStaleCache = mockCleanupStaleCache;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(200);
+      expect(mockCleanupStaleCache).toHaveBeenCalled();
+    });
+
+    test("should accept CRON_SECRET as Bearer token", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions-cleanup");
+      request.headers.set("authorization", "Bearer test-cron-secret");
+
+      const mockCleanupStaleCache = vi.fn().mockResolvedValue(undefined);
+      mockCalendarCacheEventService.prototype.cleanupStaleCache = mockCleanupStaleCache;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(200);
+      expect(mockCleanupStaleCache).toHaveBeenCalled();
+    });
+
+    test("should accept API key as query parameter", async () => {
+      const request = new NextRequest(
+        "http://localhost/api/cron/calendar-subscriptions-cleanup?apiKey=test-cron-key"
+      );
+
+      const mockCleanupStaleCache = vi.fn().mockResolvedValue(undefined);
+      mockCalendarCacheEventService.prototype.cleanupStaleCache = mockCleanupStaleCache;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(200);
+      expect(mockCleanupStaleCache).toHaveBeenCalled();
+    });
+  });
+
+  describe("Cleanup functionality", () => {
+    test("should successfully cleanup stale cache", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions-cleanup");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockCleanupStaleCache = vi.fn().mockResolvedValue(undefined);
+      mockCalendarCacheEventService.prototype.cleanupStaleCache = mockCleanupStaleCache;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(200);
+      const body = await response.json();
+      expect(body.ok).toBe(true);
+      expect(mockCleanupStaleCache).toHaveBeenCalledOnce();
+    });
+
+    test("should handle cleanup errors gracefully", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions-cleanup");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockError = new Error("Database connection failed");
+      const mockCleanupStaleCache = vi.fn().mockRejectedValue(mockError);
+      mockCalendarCacheEventService.prototype.cleanupStaleCache = mockCleanupStaleCache;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(500);
+      const body = await response.json();
+      expect(body.message).toBe("Database connection failed");
+    });
+
+    test("should handle non-Error exceptions", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions-cleanup");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockCleanupStaleCache = vi.fn().mockRejectedValue("String error");
+      mockCalendarCacheEventService.prototype.cleanupStaleCache = mockCleanupStaleCache;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(500);
+      const body = await response.json();
+      expect(body.message).toBe("Unknown error");
+    });
+  });
+
+  describe("Service instantiation", () => {
+    test("should instantiate CalendarCacheEventService with correct dependencies", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions-cleanup");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockCleanupStaleCache = vi.fn().mockResolvedValue(undefined);
+      mockCalendarCacheEventService.prototype.cleanupStaleCache = mockCleanupStaleCache;
+
+      const { GET } = await import("../route");
+      await GET(request, { params: Promise.resolve({}) });
+
+      expect(mockCalendarCacheEventService).toHaveBeenCalledWith({
+        calendarCacheEventRepository: expect.any(Object),
+      });
+    });
+  });
+});
@@ -0,0 +1,39 @@
+import type { NextRequest } from "next/server";
+import { NextResponse } from "next/server";
+
+import { CalendarCacheEventRepository } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventRepository";
+import { CalendarCacheEventService } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventService";
+import { prisma } from "@calcom/prisma";
+import { defaultResponderForAppDir } from "@calcom/web/app/api/defaultResponderForAppDir";
+
+/**
+ * Cron webhook
+ * Cleanup stale calendar cache
+ *
+ * @param request
+ * @returns
+ */
+async function getHandler(request: NextRequest) {
+  const apiKey = request.headers.get("authorization") || request.nextUrl.searchParams.get("apiKey");
+
+  if (![process.env.CRON_API_KEY, `Bearer ${process.env.CRON_SECRET}`].includes(`${apiKey}`)) {
+    return NextResponse.json({ message: "Forbidden" }, { status: 403 });
+  }
+
+  // instantiate dependencies
+  const calendarCacheEventRepository = new CalendarCacheEventRepository(prisma);
+  const calendarCacheEventService = new CalendarCacheEventService({
+    calendarCacheEventRepository,
+  });
+
+  try {
+    await calendarCacheEventService.cleanupStaleCache();
+    return NextResponse.json({ ok: true });
+  } catch (e: unknown) {
+    const message = e instanceof Error ? e.message : "Unknown error";
+    console.error(`[calendar-subscriptions-cleanup] ${message}:`, e);
+    return NextResponse.json({ message }, { status: 500 });
+  }
+}
+
+export const GET = defaultResponderForAppDir(getHandler);
@@ -0,0 +1,229 @@
+import { NextRequest } from "next/server";
+import { describe, test, expect, vi, beforeEach } from "vitest";
+
+import { CalendarSubscriptionService } from "@calcom/features/calendar-subscription/lib/CalendarSubscriptionService";
+
+vi.mock("next/server", () => ({
+  NextRequest: class MockNextRequest {
+    url: string;
+    method: string;
+    nextUrl: { searchParams: URLSearchParams };
+    private _headers: Map<string, string>;
+
+    constructor(url: string, options: { method?: string } = {}) {
+      this.url = url;
+      this.method = options.method || "GET";
+      this._headers = new Map();
+      this.nextUrl = { searchParams: new URLSearchParams(url.split("?")[1] || "") };
+    }
+
+    headers = {
+      get: (key: string): string | null => this._headers.get(key.toLowerCase()) || null,
+      set: (key: string, value: string): void => {
+        this._headers.set(key.toLowerCase(), value);
+      },
+      has: (key: string): boolean => this._headers.has(key.toLowerCase()),
+    };
+  },
+  NextResponse: {
+    json: vi.fn((body, init) => ({
+      json: vi.fn().mockResolvedValue(body),
+      status: init?.status || 200,
+    })),
+  },
+}));
+
+vi.mock("@calcom/features/calendar-subscription/lib/CalendarSubscriptionService");
+vi.mock("@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventService");
+vi.mock("@calcom/features/calendar-subscription/lib/sync/CalendarSyncService");
+vi.mock("@calcom/prisma", () => ({
+  prisma: {},
+}));
+
+const mockCalendarSubscriptionService = vi.mocked(CalendarSubscriptionService);
+
+describe("/api/cron/calendar-subscriptions", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    vi.resetModules();
+    vi.stubEnv("CRON_API_KEY", "test-cron-key");
+    vi.stubEnv("CRON_SECRET", "test-cron-secret");
+  });
+
+  describe("Authentication", () => {
+    test("should return 403 when no API key is provided", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions");
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(403);
+      const body = await response.json();
+      expect(body.message).toBe("Forbiden");
+    }, 10000);
+
+    test("should return 403 when invalid API key is provided", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions");
+      request.headers.set("authorization", "invalid-key");
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(403);
+      const body = await response.json();
+      expect(body.message).toBe("Forbiden");
+    });
+
+    test("should accept valid API key", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(true);
+      const mockCheckForNewSubscriptions = vi.fn().mockResolvedValue(undefined);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.checkForNewSubscriptions = mockCheckForNewSubscriptions;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(200);
+    });
+  });
+
+  describe("Feature flag checks", () => {
+    test("should return early when cache AND sync are disabled", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(false);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(false);
+      const mockCheckForNewSubscriptions = vi.fn();
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.checkForNewSubscriptions = mockCheckForNewSubscriptions;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(200);
+      const body = await response.json();
+      expect(body.ok).toBe(true);
+      expect(mockCheckForNewSubscriptions).not.toHaveBeenCalled();
+    });
+
+    test("should proceed when both cache and sync are enabled", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(true);
+      const mockCheckForNewSubscriptions = vi.fn().mockResolvedValue(undefined);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.checkForNewSubscriptions = mockCheckForNewSubscriptions;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(200);
+      const body = await response.json();
+      expect(body.ok).toBe(true);
+      expect(mockCheckForNewSubscriptions).toHaveBeenCalledOnce();
+    });
+  });
+
+  describe("Subscription checking functionality", () => {
+    test("should successfully check for new subscriptions", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(true);
+      const mockCheckForNewSubscriptions = vi.fn().mockResolvedValue(undefined);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.checkForNewSubscriptions = mockCheckForNewSubscriptions;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(200);
+      const body = await response.json();
+      expect(body.ok).toBe(true);
+      expect(mockCheckForNewSubscriptions).toHaveBeenCalledOnce();
+    });
+
+    test("should handle subscription checking errors gracefully", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockError = new Error("Subscription service unavailable");
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(true);
+      const mockCheckForNewSubscriptions = vi.fn().mockRejectedValue(mockError);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.checkForNewSubscriptions = mockCheckForNewSubscriptions;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(500);
+      const body = await response.json();
+      expect(body.message).toBe("Subscription service unavailable");
+    });
+
+    test("should handle non-Error exceptions", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(true);
+      const mockCheckForNewSubscriptions = vi.fn().mockRejectedValue("String error");
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.checkForNewSubscriptions = mockCheckForNewSubscriptions;
+
+      const { GET } = await import("../route");
+      const response = await GET(request, { params: Promise.resolve({}) });
+
+      expect(response.status).toBe(500);
+      const body = await response.json();
+      expect(body.message).toBe("Unknown error");
+    });
+  });
+
+  describe("Service instantiation", () => {
+    test("should instantiate all services with correct dependencies", async () => {
+      const request = new NextRequest("http://localhost/api/cron/calendar-subscriptions");
+      request.headers.set("authorization", "test-cron-key");
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(true);
+      const mockCheckForNewSubscriptions = vi.fn().mockResolvedValue(undefined);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.checkForNewSubscriptions = mockCheckForNewSubscriptions;
+
+      const { GET } = await import("../route");
+      await GET(request, { params: Promise.resolve({}) });
+
+      expect(mockCalendarSubscriptionService).toHaveBeenCalledWith({
+        adapterFactory: expect.any(Object),
+        selectedCalendarRepository: expect.any(Object),
+        featuresRepository: expect.any(Object),
+        calendarSyncService: expect.any(Object),
+        calendarCacheEventService: expect.any(Object),
+      });
+    });
+  });
+});
@@ -0,0 +1,66 @@
+import type { NextRequest } from "next/server";
+import { NextResponse } from "next/server";
+
+import { DefaultAdapterFactory } from "@calcom/features/calendar-subscription/adapters/AdaptersFactory";
+import { CalendarSubscriptionService } from "@calcom/features/calendar-subscription/lib/CalendarSubscriptionService";
+import { CalendarCacheEventRepository } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventRepository";
+import { CalendarCacheEventService } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventService";
+import { CalendarSyncService } from "@calcom/features/calendar-subscription/lib/sync/CalendarSyncService";
+import { FeaturesRepository } from "@calcom/features/flags/features.repository";
+import { SelectedCalendarRepository } from "@calcom/lib/server/repository/SelectedCalendarRepository";
+import { BookingRepository } from "@calcom/lib/server/repository/booking";
+import { prisma } from "@calcom/prisma";
+import { defaultResponderForAppDir } from "@calcom/web/app/api/defaultResponderForAppDir";
+
+/**
+ * Cron webhook
+ * Checks for new calendar subscriptions (rollouts)
+ *
+ * @param request
+ * @returns
+ */
+async function getHandler(request: NextRequest) {
+  const apiKey = request.headers.get("authorization") || request.nextUrl.searchParams.get("apiKey");
+
+  if (![process.env.CRON_API_KEY, `Bearer ${process.env.CRON_SECRET}`].includes(`${apiKey}`)) {
+    return NextResponse.json({ message: "Forbiden" }, { status: 403 });
+  }
+
+  // instantiate dependencies
+  const bookingRepository = new BookingRepository(prisma);
+  const calendarSyncService = new CalendarSyncService({
+    bookingRepository,
+  });
+  const calendarCacheEventRepository = new CalendarCacheEventRepository(prisma);
+  const calendarCacheEventService = new CalendarCacheEventService({
+    calendarCacheEventRepository,
+  });
+
+  const calendarSubscriptionService = new CalendarSubscriptionService({
+    adapterFactory: new DefaultAdapterFactory(),
+    selectedCalendarRepository: new SelectedCalendarRepository(prisma),
+    featuresRepository: new FeaturesRepository(prisma),
+    calendarSyncService,
+    calendarCacheEventService,
+  });
+
+  // are features globally enabled
+  const [isCacheEnabled, isSyncEnabled] = await Promise.all([
+    calendarSubscriptionService.isCacheEnabled(),
+    calendarSubscriptionService.isSyncEnabled(),
+  ]);
+
+  if (!isCacheEnabled && !isSyncEnabled) {
+    return NextResponse.json({ ok: true });
+  }
+
+  try {
+    await calendarSubscriptionService.checkForNewSubscriptions();
+    return NextResponse.json({ ok: true });
+  } catch (e) {
+    const message = e instanceof Error ? e.message : "Unknown error";
+    return NextResponse.json({ message }, { status: 500 });
+  }
+}
+
+export const GET = defaultResponderForAppDir(getHandler);
@@ -0,0 +1,315 @@
+import { NextRequest } from "next/server";
+import { describe, test, expect, vi, beforeEach } from "vitest";
+
+import { CalendarSubscriptionService } from "@calcom/features/calendar-subscription/lib/CalendarSubscriptionService";
+
+vi.mock("next/server", () => ({
+  NextRequest: class MockNextRequest {
+    url: string;
+    method: string;
+    nextUrl: { searchParams: URLSearchParams };
+    private _headers: Map<string, string>;
+
+    constructor(url: string, options: { method?: string } = {}) {
+      this.url = url;
+      this.method = options.method || "POST";
+      this._headers = new Map();
+      this.nextUrl = { searchParams: new URLSearchParams(url.split("?")[1] || "") };
+    }
+
+    headers = {
+      get: (key: string): string | null => this._headers.get(key.toLowerCase()) || null,
+      set: (key: string, value: string): void => {
+        this._headers.set(key.toLowerCase(), value);
+      },
+      has: (key: string): boolean => this._headers.has(key.toLowerCase()),
+    };
+  },
+  NextResponse: {
+    json: vi.fn((body, init) => ({
+      json: vi.fn().mockResolvedValue(body),
+      status: init?.status || 200,
+    })),
+  },
+}));
+
+vi.mock("@calcom/features/calendar-subscription/lib/CalendarSubscriptionService");
+vi.mock("@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventService");
+vi.mock("@calcom/features/calendar-subscription/lib/sync/CalendarSyncService");
+vi.mock("@calcom/prisma", () => ({
+  prisma: {},
+}));
+
+const mockCalendarSubscriptionService = vi.mocked(CalendarSubscriptionService);
+
+describe("/api/webhooks/calendar-subscription/[provider]", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    vi.resetModules();
+  });
+
+  describe("Provider validation", () => {
+    test("should accept google_calendar provider", async () => {
+      const request = new NextRequest("http://localhost/api/webhooks/calendar-subscription/google_calendar", {
+        method: "POST",
+      });
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(false);
+      const mockProcessWebhook = vi.fn().mockResolvedValue(undefined);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.processWebhook = mockProcessWebhook;
+
+      const { POST } = await import("../route");
+      const response = await POST(request, {
+        params: Promise.resolve({ provider: "google_calendar" }),
+      });
+
+      expect(response.status).toBe(200);
+      expect(mockProcessWebhook).toHaveBeenCalledWith("google_calendar", request);
+    }, 10000);
+
+    test("should accept office365_calendar provider", async () => {
+      const request = new NextRequest(
+        "http://localhost/api/webhooks/calendar-subscription/office365_calendar",
+        {
+          method: "POST",
+        }
+      );
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(false);
+      const mockProcessWebhook = vi.fn().mockResolvedValue(undefined);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.processWebhook = mockProcessWebhook;
+
+      const { POST } = await import("../route");
+      const response = await POST(request, {
+        params: Promise.resolve({ provider: "office365_calendar" }),
+      });
+
+      expect(response.status).toBe(200);
+      expect(mockProcessWebhook).toHaveBeenCalledWith("office365_calendar", request);
+    });
+
+    test("should reject unsupported provider", async () => {
+      const request = new NextRequest(
+        "http://localhost/api/webhooks/calendar-subscription/unsupported_calendar",
+        {
+          method: "POST",
+        }
+      );
+
+      const { POST } = await import("../route");
+      const response = await POST(request, {
+        params: Promise.resolve({ provider: "unsupported_calendar" }),
+      });
+
+      expect(response.status).toBe(400);
+      const body = await response.json();
+      expect(body.message).toBe("Unsupported provider");
+    });
+  });
+
+  describe("Feature flag handling", () => {
+    test("should return 200 when neither cache nor sync is enabled", async () => {
+      const request = new NextRequest("http://localhost/api/webhooks/calendar-subscription/google_calendar", {
+        method: "POST",
+      });
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(false);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(false);
+      const mockProcessWebhook = vi.fn();
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.processWebhook = mockProcessWebhook;
+
+      const { POST } = await import("../route");
+      const response = await POST(request, {
+        params: Promise.resolve({ provider: "google_calendar" }),
+      });
+
+      expect(response.status).toBe(200);
+      const body = await response.json();
+      expect(body.message).toBe("No cache or sync enabled");
+      expect(mockProcessWebhook).not.toHaveBeenCalled();
+    });
+
+    test("should process webhook when cache is enabled", async () => {
+      const request = new NextRequest("http://localhost/api/webhooks/calendar-subscription/google_calendar", {
+        method: "POST",
+      });
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(false);
+      const mockProcessWebhook = vi.fn().mockResolvedValue(undefined);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.processWebhook = mockProcessWebhook;
+
+      const { POST } = await import("../route");
+      const response = await POST(request, {
+        params: Promise.resolve({ provider: "google_calendar" }),
+      });
+
+      expect(response.status).toBe(200);
+      const body = await response.json();
+      expect(body.message).toBe("Webhook processed");
+      expect(mockProcessWebhook).toHaveBeenCalledWith("google_calendar", request);
+    });
+
+    test("should process webhook when sync is enabled", async () => {
+      const request = new NextRequest("http://localhost/api/webhooks/calendar-subscription/google_calendar", {
+        method: "POST",
+      });
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(false);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(true);
+      const mockProcessWebhook = vi.fn().mockResolvedValue(undefined);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.processWebhook = mockProcessWebhook;
+
+      const { POST } = await import("../route");
+      const response = await POST(request, {
+        params: Promise.resolve({ provider: "google_calendar" }),
+      });
+
+      expect(response.status).toBe(200);
+      const body = await response.json();
+      expect(body.message).toBe("Webhook processed");
+      expect(mockProcessWebhook).toHaveBeenCalledWith("google_calendar", request);
+    });
+
+    test("should process webhook when both cache and sync are enabled", async () => {
+      const request = new NextRequest("http://localhost/api/webhooks/calendar-subscription/google_calendar", {
+        method: "POST",
+      });
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(true);
+      const mockProcessWebhook = vi.fn().mockResolvedValue(undefined);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.processWebhook = mockProcessWebhook;
+
+      const { POST } = await import("../route");
+      const response = await POST(request, {
+        params: Promise.resolve({ provider: "google_calendar" }),
+      });
+
+      expect(response.status).toBe(200);
+      const body = await response.json();
+      expect(body.message).toBe("Webhook processed");
+      expect(mockProcessWebhook).toHaveBeenCalledWith("google_calendar", request);
+    });
+  });
+
+  describe("Error handling", () => {
+    test("should handle webhook processing errors gracefully", async () => {
+      const request = new NextRequest("http://localhost/api/webhooks/calendar-subscription/google_calendar", {
+        method: "POST",
+      });
+
+      const mockError = new Error("Webhook validation failed");
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(false);
+      const mockProcessWebhook = vi.fn().mockRejectedValue(mockError);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.processWebhook = mockProcessWebhook;
+
+      const { POST } = await import("../route");
+      const response = await POST(request, {
+        params: Promise.resolve({ provider: "google_calendar" }),
+      });
+
+      expect(response.status).toBe(500);
+      const body = await response.json();
+      expect(body.message).toBe("Webhook validation failed");
+    });
+
+    test("should handle non-Error exceptions", async () => {
+      const request = new NextRequest("http://localhost/api/webhooks/calendar-subscription/google_calendar", {
+        method: "POST",
+      });
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(false);
+      const mockProcessWebhook = vi.fn().mockRejectedValue("String error");
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.processWebhook = mockProcessWebhook;
+
+      const { POST } = await import("../route");
+      const response = await POST(request, {
+        params: Promise.resolve({ provider: "google_calendar" }),
+      });
+
+      expect(response.status).toBe(500);
+      const body = await response.json();
+      expect(body.message).toBe("Unknown error");
+    });
+
+    test("should handle feature flag check errors", async () => {
+      const request = new NextRequest("http://localhost/api/webhooks/calendar-subscription/google_calendar", {
+        method: "POST",
+      });
+
+      const mockError = new Error("Feature flag service unavailable");
+      const mockIsCacheEnabled = vi.fn().mockRejectedValue(mockError);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(false);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+
+      const { POST } = await import("../route");
+      const response = await POST(request, {
+        params: Promise.resolve({ provider: "google_calendar" }),
+      });
+
+      expect(response.status).toBe(500);
+      const body = await response.json();
+      expect(body.message).toBe("Feature flag service unavailable");
+    });
+  });
+
+  describe("Service instantiation", () => {
+    test("should instantiate all services with correct dependencies", async () => {
+      const request = new NextRequest("http://localhost/api/webhooks/calendar-subscription/google_calendar", {
+        method: "POST",
+      });
+
+      const mockIsCacheEnabled = vi.fn().mockResolvedValue(true);
+      const mockIsSyncEnabled = vi.fn().mockResolvedValue(false);
+      const mockProcessWebhook = vi.fn().mockResolvedValue(undefined);
+
+      mockCalendarSubscriptionService.prototype.isCacheEnabled = mockIsCacheEnabled;
+      mockCalendarSubscriptionService.prototype.isSyncEnabled = mockIsSyncEnabled;
+      mockCalendarSubscriptionService.prototype.processWebhook = mockProcessWebhook;
+
+      const { POST } = await import("../route");
+      await POST(request, {
+        params: Promise.resolve({ provider: "google_calendar" }),
+      });
+
+      expect(mockCalendarSubscriptionService).toHaveBeenCalledWith({
+        adapterFactory: expect.any(Object),
+        selectedCalendarRepository: expect.any(Object),
+        featuresRepository: expect.any(Object),
+        calendarSyncService: expect.any(Object),
+        calendarCacheEventService: expect.any(Object),
+      });
+    });
+  });
+});
@@ -0,0 +1,87 @@
+import type { Params } from "app/_types";
+import type { NextRequest } from "next/server";
+import { NextResponse } from "next/server";
+
+import type { CalendarSubscriptionProvider } from "@calcom/features/calendar-subscription/adapters/AdaptersFactory";
+import { DefaultAdapterFactory } from "@calcom/features/calendar-subscription/adapters/AdaptersFactory";
+import { CalendarSubscriptionService } from "@calcom/features/calendar-subscription/lib/CalendarSubscriptionService";
+import { CalendarCacheEventRepository } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventRepository";
+import { CalendarCacheEventService } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventService";
+import { CalendarSyncService } from "@calcom/features/calendar-subscription/lib/sync/CalendarSyncService";
+import { FeaturesRepository } from "@calcom/features/flags/features.repository";
+import logger from "@calcom/lib/logger";
+import { SelectedCalendarRepository } from "@calcom/lib/server/repository/SelectedCalendarRepository";
+import { BookingRepository } from "@calcom/lib/server/repository/booking";
+import { prisma } from "@calcom/prisma";
+import { defaultResponderForAppDir } from "@calcom/web/app/api/defaultResponderForAppDir";
+
+const log = logger.getSubLogger({ prefix: ["calendar-webhook"] });
+
+function extractAndValidateProviderFromParams(params: Params): CalendarSubscriptionProvider | null {
+  if (!("provider" in params)) {
+    return null;
+  }
+  const { provider } = params;
+  if (provider === "google_calendar" || provider === "office365_calendar") {
+    return provider;
+  }
+  return null;
+}
+
+/**
+ * Handles incoming POST requests for calendar webhooks.
+ * It processes the webhook based on the calendar provider specified in the URL.
+ * If the provider is unsupported, it returns a 400 response.
+ * If the webhook is processed successfully, it returns a 200 response.
+ * In case of errors during processing, it returns a 500 response with the error message.
+ * @param {NextRequest} request - The incoming request object.
+ * @param {Object} context - The context object containing route parameters.
+ * @param {Promise<Params>} context.params - A promise that resolves to the route parameters.
+ * @returns {Promise<NextResponse>} - A promise that resolves to the response object.
+ */
+async function postHandler(request: NextRequest, ctx: { params: Promise<Params> }) {
+  const providerFromParams = extractAndValidateProviderFromParams(await ctx.params);
+  if (!providerFromParams) {
+    return NextResponse.json({ message: "Unsupported provider" }, { status: 400 });
+  }
+
+  try {
+    // instantiate dependencies
+    const bookingRepository = new BookingRepository(prisma);
+    const calendarSyncService = new CalendarSyncService({
+      bookingRepository,
+    });
+    const calendarCacheEventRepository = new CalendarCacheEventRepository(prisma);
+    const calendarCacheEventService = new CalendarCacheEventService({
+      calendarCacheEventRepository,
+    });
+
+    const calendarSubscriptionService = new CalendarSubscriptionService({
+      adapterFactory: new DefaultAdapterFactory(),
+      selectedCalendarRepository: new SelectedCalendarRepository(prisma),
+      featuresRepository: new FeaturesRepository(prisma),
+      calendarSyncService,
+      calendarCacheEventService,
+    });
+
+    // are features globally enabled
+    const [isCacheEnabled, isSyncEnabled] = await Promise.all([
+      calendarSubscriptionService.isCacheEnabled(),
+      calendarSubscriptionService.isSyncEnabled(),
+    ]);
+
+    if (!isCacheEnabled && !isSyncEnabled) {
+      log.debug("No cache or sync enabled");
+      return NextResponse.json({ message: "No cache or sync enabled" }, { status: 200 });
+    }
+
+    await calendarSubscriptionService.processWebhook(providerFromParams, request);
+    return NextResponse.json({ message: "Webhook processed" }, { status: 200 });
+  } catch (error) {
+    log.error("Error processing webhook", { error });
+    const message = error instanceof Error ? error.message : "Unknown error";
+    return NextResponse.json({ message }, { status: 500 });
+  }
+}
+
+export const POST = defaultResponderForAppDir(postHandler);
@@ -23,9 +23,9 @@ try {
    "*/5 * * * * *",
    async function () {
      await Promise.allSettled([
-        fetchCron("/calendar-cache/cron"),
+        fetchCron("/cron/calendar-subscriptions"),
+        // fetchCron("/calendar-cache/cron"),
        // fetchCron("/cron/calVideoNoShowWebhookTriggers"),
-        //
        fetchCron("/tasks/cron"),
      ]);
    },
@@ -4,6 +4,14 @@
      "path": "/api/cron/calendar-cache-cleanup",
      "schedule": "0 5 * * *"
    },
+    {
+      "path": "/api/cron/calendar-subscriptions",
+      "schedule": "*/5 * * * *"
+    },
+    {
+      "path": "/api/cron/calendar-subscriptions-cleanup",
+      "schedule": "0 3 * * *"
+    },
    {
      "path": "/api/cron/queuedFormResponseCleanup",
      "schedule": "0 */12 * * *"
@@ -1,28 +1,17 @@
+import { CalendarSubscriptionService } from "@calcom/features/calendar-subscription/lib/CalendarSubscriptionService";
+import { CalendarCacheEventRepository } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventRepository";
+import { CalendarCacheEventService } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventService";
+import { CalendarCacheWrapper } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheWrapper";
+import { FeaturesRepository } from "@calcom/features/flags/features.repository";
 import logger from "@calcom/lib/logger";
-import type { Calendar, CalendarClass } from "@calcom/types/Calendar";
+import { prisma } from "@calcom/prisma";
+import type { Calendar } from "@calcom/types/Calendar";
 import type { CredentialForCalendarService } from "@calcom/types/Credential";

 import { CalendarServiceMap } from "../calendar.services.generated";

-interface CalendarApp {
-  lib: {
-    CalendarService: CalendarClass;
-  };
-}
-
 const log = logger.getSubLogger({ prefix: ["CalendarManager"] });

-/**
- * @see [Using type predicates](https://www.typescriptlang.org/docs/handbook/2/narrowing.html#using-type-predicates)
- */
-const isCalendarService = (x: unknown): x is CalendarApp =>
-  !!x &&
-  typeof x === "object" &&
-  "lib" in x &&
-  typeof x.lib === "object" &&
-  !!x.lib &&
-  "CalendarService" in x.lib;
-
 export const getCalendar = async (
  credential: CredentialForCalendarService | null
 ): Promise<Calendar | null> => {
@@ -53,5 +42,39 @@ export const getCalendar = async (
    return null;
  }

+  // check if Calendar Cache is supported and enabled
+  if (CalendarCacheEventService.isCalendarTypeSupported(calendarType)) {
+    log.debug(
+      `Using regular CalendarService for credential ${credential.id} (not Google or Office365 Calendar)`
+    );
+    const featuresRepository = new FeaturesRepository(prisma);
+    const [isCalendarSubscriptionCacheEnabled, isCalendarSubscriptionCacheEnabledForUser] = await Promise.all(
+      [
+        featuresRepository.checkIfFeatureIsEnabledGlobally(
+          CalendarSubscriptionService.CALENDAR_SUBSCRIPTION_CACHE_FEATURE
+        ),
+        featuresRepository.checkIfUserHasFeature(
+          credential.userId as number,
+          CalendarSubscriptionService.CALENDAR_SUBSCRIPTION_CACHE_FEATURE
+        ),
+      ]
+    );
+
+    if (isCalendarSubscriptionCacheEnabled && isCalendarSubscriptionCacheEnabledForUser) {
+      log.debug(`Calendar Cache is enabled, using CalendarCacheService for credential ${credential.id}`);
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const originalCalendar = new CalendarService(credential as any);
+      if (originalCalendar) {
+        // return cacheable calendar
+        const calendarCacheEventRepository = new CalendarCacheEventRepository(prisma);
+        return new CalendarCacheWrapper({
+          originalCalendar,
+          calendarCacheEventRepository,
+        });
+      }
+    }
+  }
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  return new CalendarService(credential as any);
 };
@@ -3,6 +3,7 @@ import { vi } from "vitest";
 const featuresRepositoryModuleMock = {
  FeaturesRepository: vi.fn().mockImplementation(() => ({
    checkIfFeatureIsEnabledGlobally: vi.fn().mockResolvedValue(true),
+    checkIfUserHasFeature: vi.fn().mockResolvedValue(true),
  })),
 };

@@ -0,0 +1,115 @@
+# Calendar Cache and Sync
+
+The **Calendar Cache and Sync** feature provides efficient calendar synchronization with intelligent caching to reduce API calls and ensure real-time updates across your Cal.com instance.
+
+## Feature Overview
+
+This feature introduces two complementary capabilities:
+
+- **Calendar Cache**: Stores calendar availability data locally to reduce external API calls and improve performance
+- **Calendar Sync**: Uses webhooks to automatically listen for calendar updates and apply changes in real-time
+
+**Key Benefits:**
+- **Efficiency**: Reduces API calls with optimized caching strategies
+- **Reliability**: Guarantees updates through webhook event delivery  
+- **Real-Time Sync**: Ensures calendars are always up-to-date with minimal latency
+- **Scalability**: Supports multiple calendars and handles high-volume updates seamlessly
+
+**Motivation:**
+By subscribing to calendars via webhooks and implementing intelligent caching, you gain a smarter, faster, and more resource-friendly way to keep your data in sync. This eliminates the need for constant polling and reduces the load on external calendar APIs while ensuring data consistency.
+
+## Environment Variables
+
+- **GOOGLE_WEBHOOK_URL**: Optional, only used for local tests. Default points to application url.
+- **GOOGLE_WEBHOOK_TOKEN**: Required, token to validate Google Webhook incoming.
+- **MICROSOFT_WEBHOOK_URL**: Optional, only used for local tests. Default points to application url.
+- **MICROSOFT_WEBHOOK_TOKEN**: Required, token to validate Microsoft Webhook incoming.
+
+## Feature Flags
+
+This feature is controlled by three feature flags that can be enabled independently:
+
+### 1. calendar-subscription-cache  
+Enables calendar cache recording and usage through calendars. This flag should be managed individually by teams.
+
+```sql
+INSERT INTO "Feature" ("slug", "enabled", "description", "type", "stale", "lastUsedAt", "createdAt", "updatedAt", "updatedBy") 
+VALUES ('calendar-subscription-cache', false, 'Allow calendar cache to be recorded and used through calendars.', 'OPERATIONAL', false, NULL, NOW(), NOW(), NULL) 
+ON CONFLICT (slug) DO NOTHING;
+```
+
+### 2. calendar-subscription-sync
+Enables calendar sync globally for all users regardless of team or organization.
+
+```sql
+INSERT INTO "Feature" ("slug", "enabled", "description", "type", "stale", "lastUsedAt", "createdAt", "updatedAt", "updatedBy") 
+VALUES ('calendar-subscription-sync', false, 'Enable calendar sync for all calendars globally.', 'OPERATIONAL', false, NULL, NOW(), NOW(), NULL) 
+ON CONFLICT (slug) DO NOTHING;
+```
+
+## Enabling Features for Specific Users
+
+To enable calendar cache features for specific users, add entries to the `UserFeatures` table:
+
+```sql
+-- Enable calendar-subscription-cache for user ID 123  
+INSERT INTO "UserFeatures" ("userId", "featureId", "assignedAt", "assignedBy", "updatedAt") 
+VALUES (123, 'calendar-subscription-cache', NOW(), 'admin', NOW()) 
+ON CONFLICT ("userId", "featureId") DO NOTHING;
+
+-- Enable calendar-subscription-sync for user ID 123
+INSERT INTO "UserFeatures" ("userId", "featureId", "assignedAt", "assignedBy", "updatedAt") 
+VALUES (123, 'calendar-subscription-sync', NOW(), 'admin', NOW()) 
+ON CONFLICT ("userId", "featureId") DO NOTHING;
+```
+
+## Enabling Features for Specific Teams
+
+To enable calendar cache features for specific teams, add entries to the `TeamFeatures` table:
+
+```sql
+-- Enable calendar-subscription-cache for team ID 456
+INSERT INTO "TeamFeatures" ("teamId", "featureId", "assignedAt", "assignedBy", "updatedAt") 
+VALUES (456, 'calendar-subscription-cache', NOW(), 'admin', NOW()) 
+ON CONFLICT ("teamId", "featureId") DO NOTHING;
+
+-- Enable calendar-subscription-sync for team ID 456
+INSERT INTO "TeamFeatures" ("teamId", "featureId", "assignedAt", "assignedBy", "updatedAt") 
+VALUES (456, 'calendar-subscription-sync', NOW(), 'admin', NOW()) 
+ON CONFLICT ("teamId", "featureId") DO NOTHING;
+```
+
+## Architecture
+
+The calendar cache and sync system consists of several key components:
+
+### Database Schema
+- **CalendarCacheEvent Table**: Stores cached calendar events with status tracking
+- **SelectedCalendar Extensions**: Additional fields for sync state and webhook management including:
+  - `channelId`: Webhook channel identifier
+  - `channelResourceId`: Resource ID for webhook subscriptions
+  - `channelResourceUri`: URI for webhook notifications
+  - `channelKind`: Type of webhook channel
+  - `channelExpiration`: Webhook subscription expiration time
+  - `syncToken`: Token for incremental sync
+  - `syncedAt`: Last successful sync timestamp
+  - `syncErrorAt`: Last sync error timestamp
+  - `syncErrorCount`: Number of consecutive sync errors
+  - `syncSubscribedAt`: Webhook subscription timestamp
+
+### Core Services
+- **CalendarCacheEventRepository**: Manages cached event storage and retrieval
+- **CalendarSubscriptionService**: Orchestrates webhook subscriptions and event processing
+- **Provider-specific Adapters**: Handle calendar-specific sync logic (Google, Office365)
+
+### Background Processes
+- **Cron Jobs**: Automated processes for cache cleanup and calendar watching
+- **Webhook Handlers**: Real-time event processing for calendar updates
+
+### Integration Points
+- **Calendar Providers**: Google Calendar, Office365, and other supported integrations
+- **Webhook Endpoints**: Receive real-time notifications from calendar providers
+- **Cache Layer**: Optimized storage for frequently accessed calendar data
+
+For detailed technical implementation, see:
+- Database migrations in `packages/prisma/migrations/`
@@ -0,0 +1,44 @@
+import { GoogleCalendarSubscriptionAdapter } from "@calcom/features/calendar-subscription/adapters/GoogleCalendarSubscription.adapter";
+import { Office365CalendarSubscriptionAdapter } from "@calcom/features/calendar-subscription/adapters/Office365CalendarSubscription.adapter";
+import type { ICalendarSubscriptionPort } from "@calcom/features/calendar-subscription/lib/CalendarSubscriptionPort.interface";
+
+export type CalendarSubscriptionProvider = "google_calendar" | "office365_calendar";
+
+export interface AdapterFactory {
+  get(provider: CalendarSubscriptionProvider): ICalendarSubscriptionPort;
+  getProviders(): CalendarSubscriptionProvider[];
+}
+
+/**
+ * Default adapter factory
+ */
+export class DefaultAdapterFactory implements AdapterFactory {
+  private singletons = {
+    google_calendar: new GoogleCalendarSubscriptionAdapter(),
+    office365_calendar: new Office365CalendarSubscriptionAdapter(),
+  } as const;
+
+  /**
+   * Returns the adapter for the given provider
+   *
+   * @param provider
+   * @returns
+   */
+  get(provider: CalendarSubscriptionProvider): ICalendarSubscriptionPort {
+    const adapter = this.singletons[provider];
+    if (!adapter) {
+      throw new Error(`No adapter found for provider ${provider}`);
+    }
+    return adapter;
+  }
+
+  /**
+   * Returns all available providers
+   *
+   * @returns
+   */
+  getProviders(): CalendarSubscriptionProvider[] {
+    const providers: CalendarSubscriptionProvider[] = ["google_calendar"];
+    return providers;
+  }
+}
@@ -0,0 +1,199 @@
+import type { calendar_v3 } from "@googleapis/calendar";
+import { v4 as uuid } from "uuid";
+
+import { CalendarAuth } from "@calcom/app-store/googlecalendar/lib/CalendarAuth";
+import dayjs from "@calcom/dayjs";
+import logger from "@calcom/lib/logger";
+import type { SelectedCalendar } from "@calcom/prisma/client";
+
+import type {
+  ICalendarSubscriptionPort,
+  CalendarSubscriptionResult,
+  CalendarSubscriptionEvent,
+  CalendarSubscriptionEventItem,
+  CalendarCredential,
+} from "../lib/CalendarSubscriptionPort.interface";
+
+const log = logger.getSubLogger({ prefix: ["GoogleCalendarSubscriptionAdapter"] });
+
+/**
+ * Google Calendar Subscription Adapter
+ *
+ * This adapter uses the Google Calendar API to create and manage calendar subscriptions
+ * @see https://developers.google.com/google-apps/calendar/quickstart/nodejs
+ */
+export class GoogleCalendarSubscriptionAdapter implements ICalendarSubscriptionPort {
+  private GOOGLE_WEBHOOK_TOKEN = process.env.GOOGLE_WEBHOOK_TOKEN;
+  private GOOGLE_WEBHOOK_URL = `${
+    process.env.GOOGLE_WEBHOOK_URL || process.env.NEXT_PUBLIC_WEBAPP_URL
+  }/api/webhooks/calendar-subscription/google_calendar`;
+
+  async validate(request: Request): Promise<boolean> {
+    const token = request?.headers?.get("X-Goog-Channel-Token");
+    if (!this.GOOGLE_WEBHOOK_TOKEN) {
+      log.warn("GOOGLE_WEBHOOK_TOKEN not configured");
+      return false;
+    }
+    if (token !== this.GOOGLE_WEBHOOK_TOKEN) {
+      log.warn("Invalid webhook token");
+      return false;
+    }
+    return true;
+  }
+
+  async extractChannelId(request: Request): Promise<string | null> {
+    const channelId = request?.headers?.get("X-Goog-Channel-ID");
+    if (!channelId) {
+      log.warn("Missing channel ID in webhook");
+      return null;
+    }
+    return channelId;
+  }
+
+  async subscribe(
+    selectedCalendar: SelectedCalendar,
+    credential: CalendarCredential
+  ): Promise<CalendarSubscriptionResult> {
+    log.debug("Attempt to subscribe to Google Calendar", { externalId: selectedCalendar.externalId });
+
+    const MONTH_IN_SECONDS = 60 * 60 * 24 * 30;
+
+    const client = await this.getClient(credential);
+    const result = await client.events.watch({
+      calendarId: selectedCalendar.externalId,
+      requestBody: {
+        id: uuid(),
+        type: "web_hook",
+        address: this.GOOGLE_WEBHOOK_URL,
+        token: this.GOOGLE_WEBHOOK_TOKEN,
+        params: {
+          ttl: MONTH_IN_SECONDS.toFixed(0),
+        },
+      },
+    });
+
+    const e = result.data?.expiration;
+    const expiration = e ? new Date(/^\d+$/.test(e) ? +e : e) : null;
+
+    return {
+      provider: "google_calendar",
+      id: result.data.id,
+      resourceId: result.data.resourceId,
+      resourceUri: result.data.resourceUri,
+      expiration,
+    };
+  }
+  async unsubscribe(selectedCalendar: SelectedCalendar, credential: CalendarCredential): Promise<void> {
+    log.debug("Attempt to unsubscribe from Google Calendar", { externalId: selectedCalendar.externalId });
+
+    const client = await this.getClient(credential);
+    await client.channels
+      .stop({
+        requestBody: {
+          id: selectedCalendar.channelId as string,
+          resourceId: selectedCalendar.channelResourceId as string,
+        },
+      })
+      .catch((err) => {
+        log.error("Error unsubscribing from Google Calendar", err);
+        throw err;
+      });
+  }
+
+  async fetchEvents(
+    selectedCalendar: SelectedCalendar,
+    credential: CalendarCredential
+  ): Promise<CalendarSubscriptionEvent> {
+    log.info("Attempt to fetch events from Google Calendar", { externalId: selectedCalendar.externalId });
+    const client = await this.getClient(credential);
+
+    let syncToken = selectedCalendar.syncToken || undefined;
+    let pageToken;
+
+    const params: calendar_v3.Params$Resource$Events$List = {
+      calendarId: selectedCalendar.externalId,
+      pageToken,
+      singleEvents: true,
+    };
+
+    if (!syncToken) {
+      const now = dayjs();
+      // first sync or unsync (3 months)
+      const threeMonths = now.add(3, "month");
+
+      const timeMinISO = now.toISOString();
+      const timeMaxISO = threeMonths.toISOString();
+      params.timeMin = timeMinISO;
+      params.timeMax = timeMaxISO;
+    } else {
+      // incremental sync
+      params.syncToken = syncToken;
+    }
+
+    const events: calendar_v3.Schema$Event[] = [];
+    do {
+      const { data }: { data: calendar_v3.Schema$Events } = await client.events.list(params);
+
+      syncToken = data.nextSyncToken || syncToken;
+      pageToken = data.nextPageToken ?? null;
+
+      events.push(...(data.items || []));
+    } while (pageToken);
+
+    return {
+      provider: "google_calendar",
+      syncToken: syncToken || null,
+      items: this.parseEvents(events),
+    };
+  }
+
+  private parseEvents(events: calendar_v3.Schema$Event[]): CalendarSubscriptionEventItem[] {
+    return events
+      .filter((event) => typeof event.id === "string" && !!event.id)
+      .map((event) => {
+        // empty or opaque is busy
+        const busy = !event.transparency || event.transparency === "opaque";
+
+        const start = event.start?.dateTime
+          ? new Date(event.start.dateTime)
+          : event.start?.date
+          ? new Date(event.start.date)
+          : new Date();
+
+        const end = event.end?.dateTime
+          ? new Date(event.end.dateTime)
+          : event.end?.date
+          ? new Date(event.end.date)
+          : new Date();
+
+        return {
+          id: event.id as string,
+          iCalUID: event.iCalUID ?? null,
+          start,
+          end,
+          busy,
+          summary: event.summary ?? null,
+          description: event.description ?? null,
+          location: event.location ?? null,
+          kind: event.kind ?? null,
+          etag: event.etag ?? null,
+          status: event.status ?? null,
+          isAllDay: typeof event.start?.date === "string" && !event.start?.dateTime ? true : false,
+          timeZone: event.start?.timeZone ?? null,
+          recurringEventId: event.recurringEventId ?? null,
+          originalStartDate: event.originalStartTime?.dateTime
+            ? new Date(event.originalStartTime.dateTime)
+            : event.originalStartTime?.date
+            ? new Date(event.originalStartTime.date)
+            : null,
+          createdAt: event.created ? new Date(event.created) : null,
+          updatedAt: event.updated ? new Date(event.updated) : null,
+        };
+      });
+  }
+
+  private async getClient(credential: CalendarCredential) {
+    const auth = new CalendarAuth(credential);
+    return await auth.getClient();
+  }
+}
@@ -0,0 +1,262 @@
+import logger from "@calcom/lib/logger";
+import type { SelectedCalendar } from "@calcom/prisma/client";
+
+import type {
+  CalendarSubscriptionEvent,
+  ICalendarSubscriptionPort,
+  CalendarSubscriptionResult,
+  CalendarCredential,
+  CalendarSubscriptionEventItem,
+} from "../lib/CalendarSubscriptionPort.interface";
+
+const log = logger.getSubLogger({ prefix: ["MicrosoftCalendarSubscriptionAdapter"] });
+
+type HttpMethod = "GET" | "POST" | "PUT" | "PATCH" | "DELETE";
+type GraphClient = { accessToken: string };
+
+interface MicrosoftGraphEvent {
+  id: string;
+  iCalUId?: string;
+  subject?: string;
+  bodyPreview?: string;
+  location?: { displayName?: string };
+  start?: { dateTime: string; timeZone: string };
+  end?: { dateTime: string; timeZone: string };
+  showAs?: "free" | "tentative" | "busy" | "oof" | "workingElsewhere" | "unknown";
+  isAllDay?: boolean;
+  isCancelled?: boolean;
+  type?: string;
+}
+
+interface MicrosoftGraphEventsResponse {
+  "@odata.nextLink"?: string;
+  "@odata.deltaLink"?: string;
+  value: MicrosoftGraphEvent[];
+}
+
+interface MicrosoftGraphSubscriptionReq {
+  resource: string;
+  changeType: string;
+  notificationUrl: string;
+  expirationDateTime: string;
+  clientState?: string;
+}
+
+interface MicrosoftGraphSubscriptionRes {
+  id: string;
+  resource: string;
+  expirationDateTime: string;
+}
+
+type AdapterConfig = {
+  baseUrl?: string;
+  webhookToken?: string | null;
+  webhookUrl?: string | null;
+  subscriptionTtlMs?: number;
+};
+
+/**
+ * Office365 Calendar Subscription Adapter
+ *
+ * This adapter uses the Microsoft Graph API to create and manage calendar subscriptions
+ * @see https://docs.microsoft.com/en-us/graph/api/resources/subscription
+ */
+export class Office365CalendarSubscriptionAdapter implements ICalendarSubscriptionPort {
+  private readonly baseUrl: string;
+  private readonly webhookToken?: string | null;
+  private readonly webhookUrl?: string | null;
+  private readonly subscriptionTtlMs: number;
+
+  constructor(cfg: AdapterConfig = {}) {
+    this.baseUrl = cfg.baseUrl ?? "https://graph.microsoft.com/v1.0";
+    this.webhookToken = cfg.webhookToken ?? process.env.MICROSOFT_WEBHOOK_TOKEN ?? null;
+    this.webhookUrl = cfg.webhookUrl ?? process.env.MICROSOFT_WEBHOOK_URL ?? null;
+    this.subscriptionTtlMs = cfg.subscriptionTtlMs ?? 3 * 24 * 60 * 60 * 1000;
+  }
+
+  async validate(request: Request): Promise<boolean> {
+    // validate handshake
+    let validationToken: string | null = null;
+    if (request?.url) {
+      try {
+        const urlObj = new URL(request.url);
+        validationToken = urlObj.searchParams.get("validationToken");
+      } catch (e) {
+        log.warn("Invalid request URL", { url: request.url });
+      }
+    }
+    if (validationToken) return true;
+
+    // validate notifications
+    const clientState =
+      request?.headers?.get("clientState") ??
+      (typeof request?.body === "object" && request.body !== null && "clientState" in request.body
+        ? (request.body as { clientState?: string }).clientState
+        : undefined);
+    if (!this.webhookToken) {
+      log.warn("MICROSOFT_WEBHOOK_TOKEN missing");
+      return false;
+    }
+    if (clientState !== this.webhookToken) {
+      log.warn("Invalid clientState");
+      return false;
+    }
+    return true;
+  }
+
+  async extractChannelId(request: Request): Promise<string | null> {
+    let id: string | null = null;
+    if (request?.body && typeof request.body === "object" && "subscriptionId" in request.body) {
+      id = (request.body as { subscriptionId?: string }).subscriptionId ?? null;
+    } else if (request?.headers?.get("subscriptionId")) {
+      id = request.headers.get("subscriptionId");
+    }
+    if (!id) {
+      log.warn("subscriptionId missing in webhook");
+    }
+    return id;
+  }
+
+  async subscribe(
+    selectedCalendar: SelectedCalendar,
+    credential: CalendarCredential
+  ): Promise<CalendarSubscriptionResult> {
+    if (!this.webhookUrl || !this.webhookToken) {
+      throw new Error("Webhook config missing (MICROSOFT_WEBHOOK_URL/TOKEN)");
+    }
+
+    const expirationDateTime = new Date(Date.now() + this.subscriptionTtlMs).toISOString();
+
+    const body: MicrosoftGraphSubscriptionReq = {
+      resource: `me/calendars/${selectedCalendar.externalId}/events`,
+      changeType: "created,updated,deleted",
+      notificationUrl: this.webhookUrl,
+      expirationDateTime,
+      clientState: this.webhookToken,
+    };
+
+    const client = await this.getGraphClient(credential);
+    const res = await this.request<MicrosoftGraphSubscriptionRes>(client, "POST", "/subscriptions", body);
+
+    return {
+      provider: "office365_calendar",
+      id: res.id,
+      resourceId: res.resource,
+      resourceUri: `${this.baseUrl}/${res.resource}`,
+      expiration: new Date(res.expirationDateTime),
+    };
+  }
+
+  async unsubscribe(selectedCalendar: SelectedCalendar, credential: CalendarCredential): Promise<void> {
+    const subId = selectedCalendar.channelResourceId;
+    if (!subId) return;
+
+    const client = await this.getGraphClient(credential);
+    await this.request(client, "DELETE", `/subscriptions/${subId}`);
+  }
+
+  async fetchEvents(
+    selectedCalendar: SelectedCalendar,
+    credential: CalendarCredential
+  ): Promise<CalendarSubscriptionEvent> {
+    const client = await this.getGraphClient(credential);
+
+    let deltaLink = selectedCalendar.syncToken ?? null;
+    const items: MicrosoftGraphEvent[] = [];
+
+    if (deltaLink) {
+      const path = this.stripBase(deltaLink);
+      const r = await this.request<MicrosoftGraphEventsResponse>(client, "GET", path);
+      items.push(...r.value);
+      deltaLink = r["@odata.deltaLink"] ?? deltaLink;
+    } else {
+      let next: string | null = `/me/calendars/${selectedCalendar.externalId}/events/delta`;
+      while (next) {
+        const r: MicrosoftGraphEventsResponse = await this.request<MicrosoftGraphEventsResponse>(
+          client,
+          "GET",
+          next
+        );
+        items.push(...r.value);
+        deltaLink = r["@odata.deltaLink"] ?? deltaLink;
+        next = r["@odata.nextLink"] ? this.stripBase(r["@odata.nextLink"]) : null;
+      }
+    }
+
+    return {
+      provider: "office365_calendar",
+      syncToken: deltaLink,
+      items: this.parseEvents(items),
+    };
+  }
+
+  private parseEvents(events: MicrosoftGraphEvent[]): CalendarSubscriptionEventItem[] {
+    return events
+      .map((e) => {
+        const busy = e.showAs === "busy" || e.showAs === "tentative" || e.showAs === "oof";
+        const start = e.start?.dateTime ? new Date(e.start.dateTime) : new Date();
+        const end = e.end?.dateTime ? new Date(e.end.dateTime) : new Date();
+
+        return {
+          id: e.id,
+          iCalUID: e.iCalUId ?? null,
+          start,
+          end,
+          busy,
+          etag: null,
+          summary: e.subject ?? null,
+          description: e.bodyPreview ?? null,
+          location: e.location?.displayName ?? null,
+          kind: e.type ?? "microsoftgraph#event",
+          status: e.isCancelled ? "cancelled" : "confirmed",
+          isAllDay: e.isAllDay ?? false,
+          timeZone: e.start?.timeZone ?? null,
+          recurringEventId: null,
+          originalStartDate: null,
+          createdAt: null,
+          updatedAt: null,
+        };
+      })
+      .filter(({ id }) => !!id);
+  }
+
+  private async getGraphClient(credential: CalendarCredential): Promise<GraphClient> {
+    const accessToken = credential.delegatedTo?.serviceAccountKey?.private_key ?? (credential.key as string);
+    if (!accessToken) throw new Error("Missing Microsoft access token");
+    return { accessToken };
+  }
+
+  private stripBase(urlOrPath: string): string {
+    return urlOrPath.startsWith("http") ? urlOrPath.replace(this.baseUrl, "") : urlOrPath;
+  }
+
+  private async request<T = unknown>(
+    client: GraphClient,
+    method: HttpMethod,
+    endpoint: string,
+    data?: unknown
+  ): Promise<T> {
+    const url = endpoint.startsWith("http") ? endpoint : `${this.baseUrl}${endpoint}`;
+    const headers: Record<string, string> = {
+      Authorization: `Bearer ${client.accessToken}`,
+      "Content-Type": "application/json",
+    };
+
+    const init: RequestInit = { method, headers };
+    if (data && (method === "POST" || method === "PUT" || method === "PATCH")) {
+      init.body = JSON.stringify(data);
+    }
+
+    const res = await fetch(url, init);
+
+    if (!res.ok) {
+      const text = await res.text().catch(() => "");
+      log.error("Graph API error", { method, endpoint: this.stripBase(url), status: res.status, text });
+      throw new Error(`Graph ${res.status} ${res.statusText}`);
+    }
+
+    if (method === "DELETE" || res.status === 204) return {} as T;
+
+    return (await res.json()) as T;
+  }
+}
@@ -0,0 +1,17 @@
+import { vi } from "vitest";
+
+export const CalendarAuth = vi.fn().mockImplementation(() => ({
+  getClient: vi.fn().mockResolvedValue({
+    events: {
+      watch: vi.fn(),
+      list: vi.fn(),
+    },
+    channels: {
+      stop: vi.fn(),
+    },
+  }),
+}));
+
+vi.doMock("@calcom/app-store/googlecalendar/lib/CalendarAuth", () => ({
+  CalendarAuth,
+}));
@@ -0,0 +1,54 @@
+import { describe, test, expect, beforeEach } from "vitest";
+
+import { DefaultAdapterFactory } from "../AdaptersFactory";
+import { GoogleCalendarSubscriptionAdapter } from "../GoogleCalendarSubscription.adapter";
+import { Office365CalendarSubscriptionAdapter } from "../Office365CalendarSubscription.adapter";
+
+describe("DefaultAdapterFactory", () => {
+  let factory: DefaultAdapterFactory;
+
+  beforeEach(() => {
+    factory = new DefaultAdapterFactory();
+  });
+
+  describe("get", () => {
+    test("should return GoogleCalendarSubscriptionAdapter for google_calendar", () => {
+      const adapter = factory.get("google_calendar");
+
+      expect(adapter).toBeInstanceOf(GoogleCalendarSubscriptionAdapter);
+    });
+
+    test("should return Office365CalendarSubscriptionAdapter for office365_calendar", () => {
+      const adapter = factory.get("office365_calendar");
+
+      expect(adapter).toBeInstanceOf(Office365CalendarSubscriptionAdapter);
+    });
+
+    test("should return the same instance for multiple calls (singleton)", () => {
+      const adapter1 = factory.get("google_calendar");
+      const adapter2 = factory.get("google_calendar");
+
+      expect(adapter1).toBe(adapter2);
+    });
+
+    test("should throw error for unsupported provider", () => {
+      expect(() => {
+        factory.get("unsupported_calendar" as never);
+      }).toThrow("No adapter found for provider unsupported_calendar");
+    });
+  });
+
+  describe("getProviders", () => {
+    test("should return all available providers", () => {
+      const providers = factory.getProviders();
+
+      expect(providers).toEqual(["google_calendar"]);
+    });
+
+    test("should return array with correct length", () => {
+      const providers = factory.getProviders();
+
+      expect(providers).toHaveLength(1);
+    });
+  });
+});
@@ -0,0 +1,497 @@
+import "../__mocks__/CalendarAuth";
+
+import { beforeEach, describe, expect, test, vi } from "vitest";
+
+import type { SelectedCalendar } from "@calcom/prisma/client";
+import type { CredentialForCalendarServiceWithEmail } from "@calcom/types/Credential";
+
+import { GoogleCalendarSubscriptionAdapter } from "../GoogleCalendarSubscription.adapter";
+
+vi.mock("uuid", () => ({
+  v4: vi.fn().mockReturnValue("test-uuid"),
+}));
+
+const mockSelectedCalendar: SelectedCalendar = {
+  id: "test-calendar-id",
+  userId: 1,
+  credentialId: 1,
+  integration: "google_calendar",
+  externalId: "test@example.com",
+  eventTypeId: null,
+  delegationCredentialId: null,
+  domainWideDelegationCredentialId: null,
+  googleChannelId: null,
+  googleChannelKind: null,
+  googleChannelResourceId: null,
+  googleChannelResourceUri: null,
+  googleChannelExpiration: null,
+  error: null,
+  lastErrorAt: null,
+  watchAttempts: 0,
+  maxAttempts: 3,
+  unwatchAttempts: 0,
+  createdAt: new Date(),
+  updatedAt: new Date(),
+  channelId: "test-channel-id",
+  channelKind: "web_hook",
+  channelResourceId: "test-resource-id",
+  channelResourceUri: "test-resource-uri",
+  channelExpiration: new Date(Date.now() + 86400000),
+  syncSubscribedAt: new Date(),
+  syncToken: "test-sync-token",
+  syncedAt: new Date(),
+  syncErrorAt: null,
+  syncErrorCount: 0,
+};
+
+const mockCredential = {
+  id: 1,
+  key: { access_token: "test-token" },
+  user: { email: "test@example.com" },
+  delegatedTo: null,
+  type: null,
+  teamId: null,
+} as unknown as CredentialForCalendarServiceWithEmail;
+
+describe("GoogleCalendarSubscriptionAdapter", () => {
+  let adapter: GoogleCalendarSubscriptionAdapter;
+  let mockClient: {
+    events: {
+      watch: ReturnType<typeof vi.fn>;
+      list: ReturnType<typeof vi.fn>;
+    };
+    channels: {
+      stop: ReturnType<typeof vi.fn>;
+    };
+  };
+
+  beforeEach(async () => {
+    process.env.GOOGLE_WEBHOOK_TOKEN = "test-webhook-token";
+    process.env.GOOGLE_WEBHOOK_URL = "https://example.com";
+
+    mockClient = {
+      events: {
+        watch: vi.fn(),
+        list: vi.fn(),
+      },
+      channels: {
+        stop: vi.fn(),
+      },
+    };
+
+    const { CalendarAuth } = await import("../__mocks__/CalendarAuth");
+    vi.mocked(CalendarAuth).mockImplementation(() => ({
+      getClient: vi.fn().mockResolvedValue(mockClient),
+    }));
+
+    adapter = new GoogleCalendarSubscriptionAdapter();
+    vi.clearAllMocks();
+  });
+
+  describe("validate", () => {
+    test("should validate webhook with correct token", async () => {
+      const mockRequest = {
+        headers: {
+          get: vi.fn().mockReturnValue("test-webhook-token"),
+        },
+      } as unknown as Request;
+
+      const result = await adapter.validate(mockRequest);
+
+      expect(result).toBe(true);
+      expect(mockRequest.headers.get).toHaveBeenCalledWith("X-Goog-Channel-Token");
+    });
+
+    test("should reject webhook with incorrect token", async () => {
+      const mockRequest = {
+        headers: {
+          get: vi.fn().mockReturnValue("wrong-token"),
+        },
+      } as unknown as Request;
+
+      const result = await adapter.validate(mockRequest);
+
+      expect(result).toBe(false);
+    });
+
+    test("should reject webhook when token is not configured", async () => {
+      delete process.env.GOOGLE_WEBHOOK_TOKEN;
+      adapter = new GoogleCalendarSubscriptionAdapter();
+
+      const mockRequest = {
+        headers: {
+          get: vi.fn().mockReturnValue("test-webhook-token"),
+        },
+      } as unknown as Request;
+
+      const result = await adapter.validate(mockRequest);
+
+      expect(result).toBe(false);
+    });
+
+    test("should reject webhook with missing token header", async () => {
+      const mockRequest = {
+        headers: {
+          get: vi.fn().mockReturnValue(null),
+        },
+      } as unknown as Request;
+
+      const result = await adapter.validate(mockRequest);
+
+      expect(result).toBe(false);
+    });
+  });
+
+  describe("extractChannelId", () => {
+    test("should extract channel ID from webhook headers", async () => {
+      const mockRequest = {
+        headers: {
+          get: vi.fn().mockReturnValue("test-channel-id"),
+        },
+      } as unknown as Request;
+
+      const result = await adapter.extractChannelId(mockRequest);
+
+      expect(result).toBe("test-channel-id");
+      expect(mockRequest.headers.get).toHaveBeenCalledWith("X-Goog-Channel-ID");
+    });
+
+    test("should return null when channel ID is missing", async () => {
+      const mockRequest = {
+        headers: {
+          get: vi.fn().mockReturnValue(null),
+        },
+      } as unknown as Request;
+
+      const result = await adapter.extractChannelId(mockRequest);
+
+      expect(result).toBeNull();
+    });
+  });
+
+  describe("subscribe", () => {
+    test("should successfully subscribe to calendar", async () => {
+      const mockWatchResponse = {
+        data: {
+          id: "test-channel-id",
+          resourceId: "test-resource-id",
+          resourceUri: "test-resource-uri",
+          expiration: "1640995200000",
+        },
+      };
+
+      mockClient.events.watch.mockResolvedValue(mockWatchResponse);
+
+      const result = await adapter.subscribe(mockSelectedCalendar, mockCredential);
+
+      expect(mockClient.events.watch).toHaveBeenCalledWith({
+        calendarId: "test@example.com",
+        requestBody: {
+          id: "test-uuid",
+          type: "web_hook",
+          address: "https://example.com/api/webhooks/calendar-subscription/google_calendar",
+          token: "test-webhook-token",
+          params: {
+            ttl: "2592000",
+          },
+        },
+      });
+
+      expect(result).toEqual({
+        provider: "google_calendar",
+        id: "test-channel-id",
+        resourceId: "test-resource-id",
+        resourceUri: "test-resource-uri",
+        expiration: new Date(1640995200000),
+      });
+    });
+
+    test("should handle expiration as ISO string", async () => {
+      const mockWatchResponse = {
+        data: {
+          id: "test-channel-id",
+          resourceId: "test-resource-id",
+          resourceUri: "test-resource-uri",
+          expiration: "2023-12-01T10:00:00Z",
+        },
+      };
+
+      mockClient.events.watch.mockResolvedValue(mockWatchResponse);
+
+      const result = await adapter.subscribe(mockSelectedCalendar, mockCredential);
+
+      expect(result.expiration).toEqual(new Date("2023-12-01T10:00:00Z"));
+    });
+
+    test("should handle missing expiration", async () => {
+      const mockWatchResponse = {
+        data: {
+          id: "test-channel-id",
+          resourceId: "test-resource-id",
+          resourceUri: "test-resource-uri",
+        },
+      };
+
+      mockClient.events.watch.mockResolvedValue(mockWatchResponse);
+
+      const result = await adapter.subscribe(mockSelectedCalendar, mockCredential);
+
+      expect(result.expiration).toBeNull();
+    });
+  });
+
+  describe("unsubscribe", () => {
+    test("should successfully unsubscribe from calendar", async () => {
+      mockClient.channels.stop.mockResolvedValue({});
+
+      await adapter.unsubscribe(mockSelectedCalendar, mockCredential);
+
+      expect(mockClient.channels.stop).toHaveBeenCalledWith({
+        requestBody: {
+          id: "test-channel-id",
+          resourceId: "test-resource-id",
+        },
+      });
+    });
+
+    test("should handle unsubscribe errors", async () => {
+      const error = new Error("Unsubscribe failed");
+      mockClient.channels.stop.mockRejectedValue(error);
+
+      await expect(adapter.unsubscribe(mockSelectedCalendar, mockCredential)).rejects.toThrow(
+        "Unsubscribe failed"
+      );
+    });
+  });
+
+  describe("fetchEvents", () => {
+    test("should fetch events with sync token", async () => {
+      const mockEventsResponse = {
+        data: {
+          nextSyncToken: "new-sync-token",
+          items: [
+            {
+              id: "event-1",
+              iCalUID: "event-1@cal.com",
+              summary: "Test Event",
+              description: "Test Description",
+              location: "Test Location",
+              start: {
+                dateTime: "2023-12-01T10:00:00Z",
+                timeZone: "UTC",
+              },
+              end: {
+                dateTime: "2023-12-01T11:00:00Z",
+              },
+              status: "confirmed",
+              transparency: "opaque",
+              kind: "calendar#event",
+              etag: "test-etag",
+              created: "2023-12-01T09:00:00Z",
+              updated: "2023-12-01T09:30:00Z",
+            },
+          ],
+        },
+      };
+
+      mockClient.events.list.mockResolvedValue(mockEventsResponse);
+
+      const result = await adapter.fetchEvents(mockSelectedCalendar, mockCredential);
+
+      expect(mockClient.events.list).toHaveBeenCalledWith({
+        calendarId: "test@example.com",
+        pageToken: undefined,
+        singleEvents: true,
+        syncToken: "test-sync-token",
+      });
+
+      expect(result).toEqual({
+        provider: "google_calendar",
+        syncToken: "new-sync-token",
+        items: [
+          {
+            id: "event-1",
+            iCalUID: "event-1@cal.com",
+            start: new Date("2023-12-01T10:00:00Z"),
+            end: new Date("2023-12-01T11:00:00Z"),
+            busy: true,
+            summary: "Test Event",
+            description: "Test Description",
+            location: "Test Location",
+            kind: "calendar#event",
+            etag: "test-etag",
+            status: "confirmed",
+            isAllDay: false,
+            timeZone: "UTC",
+            recurringEventId: null,
+            originalStartDate: null,
+            createdAt: new Date("2023-12-01T09:00:00Z"),
+            updatedAt: new Date("2023-12-01T09:30:00Z"),
+          },
+        ],
+      });
+    });
+
+    test("should fetch events without sync token (initial sync)", async () => {
+      const calendarWithoutSyncToken = {
+        ...mockSelectedCalendar,
+        syncToken: null,
+      };
+
+      const mockEventsResponse = {
+        data: {
+          nextSyncToken: "initial-sync-token",
+          items: [],
+        },
+      };
+
+      mockClient.events.list.mockResolvedValue(mockEventsResponse);
+
+      const result = await adapter.fetchEvents(calendarWithoutSyncToken, mockCredential);
+
+      expect(mockClient.events.list).toHaveBeenCalledWith({
+        calendarId: "test@example.com",
+        pageToken: undefined,
+        singleEvents: true,
+        timeMin: expect.any(String),
+        timeMax: expect.any(String),
+      });
+
+      expect(result.syncToken).toBe("initial-sync-token");
+    });
+
+    test("should handle all-day events", async () => {
+      const mockEventsResponse = {
+        data: {
+          nextSyncToken: "new-sync-token",
+          items: [
+            {
+              id: "event-1",
+              iCalUID: "event-1@cal.com",
+              summary: "All Day Event",
+              start: {
+                date: "2023-12-01",
+              },
+              end: {
+                date: "2023-12-02",
+              },
+              status: "confirmed",
+              transparency: "opaque",
+            },
+          ],
+        },
+      };
+
+      mockClient.events.list.mockResolvedValue(mockEventsResponse);
+
+      const result = await adapter.fetchEvents(mockSelectedCalendar, mockCredential);
+
+      expect(result.items[0].isAllDay).toBe(true);
+      expect(result.items[0].start).toEqual(new Date("2023-12-01"));
+      expect(result.items[0].end).toEqual(new Date("2023-12-02"));
+    });
+
+    test("should handle free events (transparent)", async () => {
+      const mockEventsResponse = {
+        data: {
+          nextSyncToken: "new-sync-token",
+          items: [
+            {
+              id: "event-1",
+              iCalUID: "event-1@cal.com",
+              summary: "Free Event",
+              start: {
+                dateTime: "2023-12-01T10:00:00Z",
+              },
+              end: {
+                dateTime: "2023-12-01T11:00:00Z",
+              },
+              status: "confirmed",
+              transparency: "transparent",
+            },
+          ],
+        },
+      };
+
+      mockClient.events.list.mockResolvedValue(mockEventsResponse);
+
+      const result = await adapter.fetchEvents(mockSelectedCalendar, mockCredential);
+
+      expect(result.items[0].busy).toBe(false);
+    });
+
+    test("should handle pagination", async () => {
+      const mockEventsResponse1 = {
+        data: {
+          nextPageToken: "page-2",
+          items: [
+            {
+              id: "event-1",
+              summary: "Event 1",
+              start: { dateTime: "2023-12-01T10:00:00Z" },
+              end: { dateTime: "2023-12-01T11:00:00Z" },
+            },
+          ],
+        },
+      };
+
+      const mockEventsResponse2 = {
+        data: {
+          nextSyncToken: "final-sync-token",
+          items: [
+            {
+              id: "event-2",
+              summary: "Event 2",
+              start: { dateTime: "2023-12-01T12:00:00Z" },
+              end: { dateTime: "2023-12-01T13:00:00Z" },
+            },
+          ],
+        },
+      };
+
+      mockClient.events.list
+        .mockResolvedValueOnce(mockEventsResponse1)
+        .mockResolvedValueOnce(mockEventsResponse2);
+
+      const result = await adapter.fetchEvents(mockSelectedCalendar, mockCredential);
+
+      expect(mockClient.events.list).toHaveBeenCalledTimes(2);
+      expect(result.items).toHaveLength(2);
+      expect(result.syncToken).toBe("final-sync-token");
+    });
+
+    test("should filter out events without ID", async () => {
+      const mockEventsResponse = {
+        data: {
+          nextSyncToken: "new-sync-token",
+          items: [
+            {
+              id: "event-1",
+              summary: "Valid Event",
+              start: { dateTime: "2023-12-01T10:00:00Z" },
+              end: { dateTime: "2023-12-01T11:00:00Z" },
+            },
+            {
+              summary: "Invalid Event",
+              start: { dateTime: "2023-12-01T12:00:00Z" },
+              end: { dateTime: "2023-12-01T13:00:00Z" },
+            },
+            {
+              id: "",
+              summary: "Empty ID Event",
+              start: { dateTime: "2023-12-01T14:00:00Z" },
+              end: { dateTime: "2023-12-01T15:00:00Z" },
+            },
+          ],
+        },
+      };
+
+      mockClient.events.list.mockResolvedValue(mockEventsResponse);
+
+      const result = await adapter.fetchEvents(mockSelectedCalendar, mockCredential);
+
+      expect(result.items).toHaveLength(1);
+      expect(result.items[0].id).toBe("event-1");
+    });
+  });
+});
@@ -0,0 +1,49 @@
+import { describe, test, expect } from "vitest";
+
+import type { SelectedCalendar } from "@calcom/prisma/client";
+
+const _mockSelectedCalendar: SelectedCalendar = {
+  id: "test-calendar-id",
+  userId: 1,
+  credentialId: 1,
+  integration: "office365_calendar",
+  externalId: "test@example.com",
+  eventTypeId: null,
+  delegationCredentialId: null,
+  domainWideDelegationCredentialId: null,
+  googleChannelId: null,
+  googleChannelKind: null,
+  googleChannelResourceId: null,
+  googleChannelResourceUri: null,
+  googleChannelExpiration: null,
+  error: null,
+  lastErrorAt: null,
+  watchAttempts: 0,
+  maxAttempts: 3,
+  unwatchAttempts: 0,
+  createdAt: new Date(),
+  updatedAt: new Date(),
+  channelId: "test-channel-id",
+  channelKind: "web_hook",
+  channelResourceId: "test-resource-id",
+  channelResourceUri: "test-resource-uri",
+  channelExpiration: new Date(Date.now() + 86400000),
+  syncSubscribedAt: new Date(),
+  syncToken: "test-sync-token",
+  syncedAt: new Date(),
+  syncErrorAt: null,
+  syncErrorCount: 0,
+};
+
+const _mockCredential = {
+  id: 1,
+  key: { access_token: "test-token" },
+  user: { email: "test@example.com" },
+  delegatedTo: null,
+};
+
+describe("Office365CalendarSubscriptionAdapter", () => {
+  test("should be a placeholder test", () => {
+    expect(true).toBe(true);
+  });
+});
@@ -0,0 +1,83 @@
+import type { CalendarSubscriptionProvider } from "@calcom/features/calendar-subscription/adapters/AdaptersFactory";
+import type { SelectedCalendar } from "@calcom/prisma/client";
+import type {
+  CredentialForCalendarService,
+  CredentialForCalendarServiceWithEmail,
+} from "@calcom/types/Credential";
+
+export type CalendarSubscriptionResult = {
+  provider: CalendarSubscriptionProvider;
+  id?: string | null;
+  resourceId?: string | null;
+  resourceUri?: string | null;
+  expiration?: Date | null;
+};
+
+export type CalendarSubscriptionEventItem = {
+  id: string;
+  iCalUID: string | null;
+  start?: Date;
+  end?: Date;
+  busy: boolean;
+  isAllDay: boolean;
+  summary: string | null;
+  description: string | null;
+  kind: string | null;
+  etag: string | null;
+  status: string | null;
+  location: string | null;
+  originalStartDate: Date | null;
+  recurringEventId: string | null;
+  timeZone: string | null;
+  createdAt: Date | null;
+  updatedAt: Date | null;
+};
+
+export type CalendarSubscriptionEvent = {
+  provider: CalendarSubscriptionProvider;
+  syncToken: string | null;
+  items: CalendarSubscriptionEventItem[];
+};
+
+export type CalendarCredential = CredentialForCalendarServiceWithEmail;
+
+/**
+ * Calendar Subscription Port
+ */
+export interface ICalendarSubscriptionPort {
+  /**
+   * Validates a webhook request
+   * @param context
+   */
+  validate(context: Request): Promise<boolean>;
+
+  /**
+   * Extracts channel ID from a webhook request
+   * @param request
+   */
+  extractChannelId(context: Request): Promise<string | null>;
+
+  /**
+   * Subscribes to a calendar
+   * @param selectedCalendar
+   */
+  subscribe(
+    selectedCalendar: SelectedCalendar,
+    credential: CalendarCredential
+  ): Promise<CalendarSubscriptionResult>;
+
+  /**
+   * Unsubscribes from a calendar
+   * @param selectedCalendar
+   */
+  unsubscribe(selectedCalendar: SelectedCalendar, credential: CalendarCredential): Promise<void>;
+
+  /**
+   * Pulls events from a calendar
+   * @param selectedCalendar
+   */
+  fetchEvents(
+    selectedCalendar: SelectedCalendar,
+    credential: CredentialForCalendarService
+  ): Promise<CalendarSubscriptionEvent>;
+}
@@ -0,0 +1,255 @@
+import type {
+  AdapterFactory,
+  CalendarSubscriptionProvider,
+} from "@calcom/features/calendar-subscription/adapters/AdaptersFactory";
+import type {
+  CalendarCredential,
+  CalendarSubscriptionEvent,
+} from "@calcom/features/calendar-subscription/lib/CalendarSubscriptionPort.interface";
+import type { CalendarCacheEventService } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventService";
+import type { CalendarSyncService } from "@calcom/features/calendar-subscription/lib/sync/CalendarSyncService";
+import type { FeaturesRepository } from "@calcom/features/flags/features.repository";
+import { getCredentialForCalendarCache } from "@calcom/lib/delegationCredential/server";
+import logger from "@calcom/lib/logger";
+import type { ISelectedCalendarRepository } from "@calcom/lib/server/repository/SelectedCalendarRepository.interface";
+import type { SelectedCalendar } from "@calcom/prisma/client";
+
+const log = logger.getSubLogger({ prefix: ["CalendarSubscriptionService"] });
+
+export class CalendarSubscriptionService {
+  static CALENDAR_SUBSCRIPTION_CACHE_FEATURE = "calendar-subscription-cache" as const;
+  static CALENDAR_SUBSCRIPTION_SYNC_FEATURE = "calendar-subscription-sync" as const;
+
+  constructor(
+    private deps: {
+      adapterFactory: AdapterFactory;
+      selectedCalendarRepository: ISelectedCalendarRepository;
+      featuresRepository: FeaturesRepository;
+      calendarCacheEventService: CalendarCacheEventService;
+      calendarSyncService: CalendarSyncService;
+    }
+  ) {}
+
+  /**
+   * Subscribe to a calendar
+   */
+  async subscribe(selectedCalendarId: string): Promise<void> {
+    log.debug("subscribe", { selectedCalendarId });
+    const selectedCalendar = await this.deps.selectedCalendarRepository.findByIdWithCredentials(
+      selectedCalendarId
+    );
+    if (!selectedCalendar?.credentialId) {
+      log.debug("Selected calendar not found", { selectedCalendarId });
+      return;
+    }
+
+    const credential = await this.getCredential(selectedCalendar.credentialId);
+    if (!credential) {
+      log.debug("Calendar credential not found", { selectedCalendarId });
+      return;
+    }
+
+    const calendarSubscriptionAdapter = this.deps.adapterFactory.get(
+      selectedCalendar.integration as CalendarSubscriptionProvider
+    );
+    const res = await calendarSubscriptionAdapter.subscribe(selectedCalendar, credential);
+
+    await this.deps.selectedCalendarRepository.updateSubscription(selectedCalendarId, {
+      channelId: res?.id,
+      channelResourceId: res?.resourceId,
+      channelResourceUri: res?.resourceUri,
+      channelKind: res?.provider,
+      channelExpiration: res?.expiration,
+      syncSubscribedAt: new Date(),
+    });
+
+    // initial event loading
+    await this.processEvents(selectedCalendar);
+  }
+
+  /**
+   * Unsubscribe from a calendar
+   */
+  async unsubscribe(selectedCalendarId: string): Promise<void> {
+    log.debug("unsubscribe", { selectedCalendarId });
+    const selectedCalendar = await this.deps.selectedCalendarRepository.findByIdWithCredentials(
+      selectedCalendarId
+    );
+    if (!selectedCalendar?.credentialId) return;
+
+    const credential = await this.getCredential(selectedCalendar.credentialId);
+    if (!credential) return;
+
+    const calendarSubscriptionAdapter = this.deps.adapterFactory.get(
+      selectedCalendar.integration as CalendarSubscriptionProvider
+    );
+
+    await Promise.all([
+      calendarSubscriptionAdapter.unsubscribe(selectedCalendar, credential),
+      this.deps.selectedCalendarRepository.updateSubscription(selectedCalendarId, {
+        syncSubscribedAt: null,
+      }),
+    ]);
+
+    // cleanup cache after unsubscribe
+    if (await this.isCacheEnabled()) {
+      log.debug("cleanupCache", { selectedCalendarId });
+      await this.deps.calendarCacheEventService.cleanupCache(selectedCalendar);
+    }
+  }
+
+  /**
+   * Process webhook
+   */
+  async processWebhook(provider: CalendarSubscriptionProvider, request: Request) {
+    log.debug("processWebhook", { provider });
+    const calendarSubscriptionAdapter = this.deps.adapterFactory.get(provider);
+
+    const isValid = await calendarSubscriptionAdapter.validate(request);
+    if (!isValid) throw new Error("Invalid webhook request");
+
+    const channelId = await calendarSubscriptionAdapter.extractChannelId(request);
+    if (!channelId) throw new Error("Missing channel ID in webhook");
+
+    log.debug("Processing webhook", { channelId });
+    const selectedCalendar = await this.deps.selectedCalendarRepository.findByChannelId(channelId);
+    // it maybe caused by an old subscription being triggered
+    if (!selectedCalendar) return null;
+
+    // incremental event loading
+    await this.processEvents(selectedCalendar);
+  }
+
+  /**
+   * Process events
+   * - fetch events from calendar
+   * - process events
+   * - update selected calendar
+   * - update cache
+   * - update sync
+   */
+  async processEvents(selectedCalendar: SelectedCalendar): Promise<void> {
+    const calendarSubscriptionAdapter = this.deps.adapterFactory.get(
+      selectedCalendar.integration as CalendarSubscriptionProvider
+    );
+
+    if (!selectedCalendar.credentialId) {
+      log.debug("Selected calendar credential not found", { channelId: selectedCalendar.channelId });
+      return;
+    }
+    // for cache the feature should be enabled globally and by user/team features
+    const [cacheEnabled, syncEnabled, cacheEnabledForUser] = await Promise.all([
+      this.isCacheEnabled(),
+      this.isSyncEnabled(),
+      this.isCacheEnabledForUser(selectedCalendar.userId),
+    ]);
+
+    if (!cacheEnabled && !syncEnabled) {
+      log.info("Cache and sync are globally disabled", { channelId: selectedCalendar.channelId });
+      return;
+    }
+
+    log.debug("Processing events", { channelId: selectedCalendar.channelId });
+    const credential = await this.getCredential(selectedCalendar.credentialId);
+    if (!credential) return;
+
+    let events: CalendarSubscriptionEvent | null = null;
+    try {
+      events = await calendarSubscriptionAdapter.fetchEvents(selectedCalendar, credential);
+    } catch (err) {
+      log.debug("Error fetching events", { channelId: selectedCalendar.channelId, err });
+      await this.deps.selectedCalendarRepository.updateSyncStatus(selectedCalendar.id, {
+        syncErrorAt: new Date(),
+        syncErrorCount: { increment: 1 },
+      });
+      throw err;
+    }
+
+    if (!events?.items?.length) {
+      log.debug("No events fetched", { channelId: selectedCalendar.channelId });
+      return;
+    }
+
+    log.debug("Processing events", { channelId: selectedCalendar.channelId, count: events.items.length });
+    await this.deps.selectedCalendarRepository.updateSyncStatus(selectedCalendar.id, {
+      syncToken: events.syncToken || selectedCalendar.syncToken,
+      syncedAt: new Date(),
+      syncErrorAt: null,
+      syncErrorCount: 0,
+    });
+
+    // it requires both global and team/user feature cache enabled
+    if (cacheEnabled && cacheEnabledForUser) {
+      log.debug("Caching events", { count: events.items.length });
+      await this.deps.calendarCacheEventService.handleEvents(selectedCalendar, events.items);
+    }
+
+    if (syncEnabled) {
+      log.debug("Syncing events", { count: events.items.length });
+      await this.deps.calendarSyncService.handleEvents(selectedCalendar, events.items);
+    }
+  }
+
+  /**
+   * Subscribe periodically to new calendars
+   */
+  async checkForNewSubscriptions() {
+    const rows = await this.deps.selectedCalendarRepository.findNextSubscriptionBatch({
+      take: 100,
+      integrations: this.deps.adapterFactory.getProviders(),
+    });
+    log.debug("checkForNewSubscriptions", { count: rows.length });
+    await Promise.allSettled(rows.map(({ id }) => this.subscribe(id)));
+  }
+
+  /**
+   * Check if cache is enabled
+   * @returns true if cache is enabled
+   */
+  async isCacheEnabled(): Promise<boolean> {
+    return this.deps.featuresRepository.checkIfFeatureIsEnabledGlobally(
+      CalendarSubscriptionService.CALENDAR_SUBSCRIPTION_CACHE_FEATURE
+    );
+  }
+
+  /**
+   * Check if cache is enabled for user
+   * @returns true if cache is enabled
+   */
+  async isCacheEnabledForUser(userId: number): Promise<boolean> {
+    return this.deps.featuresRepository.checkIfUserHasFeature(
+      userId,
+      CalendarSubscriptionService.CALENDAR_SUBSCRIPTION_CACHE_FEATURE
+    );
+  }
+
+  /**
+   * Check if sync is enabled
+   * @returns true if sync is enabled
+   */
+  async isSyncEnabled(): Promise<boolean> {
+    return this.deps.featuresRepository.checkIfFeatureIsEnabledGlobally(
+      CalendarSubscriptionService.CALENDAR_SUBSCRIPTION_SYNC_FEATURE
+    );
+  }
+
+  /**
+   * Get credential with delegation if available
+   */
+  private async getCredential(credentialId: number): Promise<CalendarCredential | null> {
+    const credential = await getCredentialForCalendarCache({ credentialId });
+    if (!credential) return null;
+    return {
+      ...credential,
+      delegatedTo: credential.delegatedTo?.serviceAccountKey?.client_email
+        ? {
+            serviceAccountKey: {
+              client_email: credential.delegatedTo.serviceAccountKey.client_email,
+              client_id: credential.delegatedTo.serviceAccountKey.client_id,
+              private_key: credential.delegatedTo.serviceAccountKey.private_key,
+            },
+          }
+        : null,
+    };
+  }
+}
@@ -0,0 +1,12 @@
+import { vi } from "vitest";
+
+export const getCredentialForCalendarCache = vi.fn().mockResolvedValue({
+  id: 1,
+  key: { access_token: "test-token" },
+  user: { email: "test@example.com" },
+  delegatedTo: null,
+});
+
+vi.doMock("@calcom/lib/delegationCredential/server", () => ({
+  getCredentialForCalendarCache,
+}));
@@ -0,0 +1,420 @@
+import "../__mocks__/delegationCredential";
+
+import { describe, test, expect, vi, beforeEach } from "vitest";
+
+import type { AdapterFactory } from "@calcom/features/calendar-subscription/adapters/AdaptersFactory";
+import type { CalendarCacheEventService } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventService";
+import type { CalendarSyncService } from "@calcom/features/calendar-subscription/lib/sync/CalendarSyncService";
+import type { FeaturesRepository } from "@calcom/features/flags/features.repository";
+import type { ISelectedCalendarRepository } from "@calcom/lib/server/repository/SelectedCalendarRepository.interface";
+import type { SelectedCalendar } from "@calcom/prisma/client";
+
+import { CalendarSubscriptionService } from "../CalendarSubscriptionService";
+
+const mockSelectedCalendar: SelectedCalendar = {
+  id: "test-calendar-id",
+  userId: 1,
+  credentialId: 1,
+  integration: "google_calendar",
+  externalId: "test@example.com",
+  eventTypeId: null,
+  delegationCredentialId: null,
+  domainWideDelegationCredentialId: null,
+  googleChannelId: null,
+  googleChannelKind: null,
+  googleChannelResourceId: null,
+  googleChannelResourceUri: null,
+  googleChannelExpiration: null,
+  error: null,
+  lastErrorAt: null,
+  watchAttempts: 0,
+  maxAttempts: 3,
+  unwatchAttempts: 0,
+  createdAt: new Date(),
+  updatedAt: new Date(),
+  channelId: "test-channel-id",
+  channelKind: "web_hook",
+  channelResourceId: "test-resource-id",
+  channelResourceUri: "test-resource-uri",
+  channelExpiration: new Date(Date.now() + 86400000),
+  syncSubscribedAt: new Date(),
+  syncToken: "test-sync-token",
+  syncedAt: new Date(),
+  syncErrorAt: null,
+  syncErrorCount: 0,
+};
+
+const mockCredential = {
+  id: 1,
+  key: { access_token: "test-token" },
+  user: { email: "test@example.com" },
+  delegatedTo: null,
+};
+
+const mockSubscriptionResult = {
+  provider: "google_calendar" as const,
+  id: "test-channel-id",
+  resourceId: "test-resource-id",
+  resourceUri: "test-resource-uri",
+  expiration: new Date(Date.now() + 86400000),
+};
+
+const mockEvents = {
+  provider: "google_calendar" as const,
+  syncToken: "new-sync-token",
+  items: [
+    {
+      id: "event-1",
+      iCalUID: "event-1@cal.com",
+      start: new Date(),
+      end: new Date(Date.now() + 3600000),
+      busy: true,
+      summary: "Test Event",
+      description: "Test Description",
+      location: "Test Location",
+      status: "confirmed",
+      isAllDay: false,
+      timeZone: "UTC",
+      recurringEventId: null,
+      originalStartDate: null,
+      createdAt: new Date(),
+      updatedAt: new Date(),
+      etag: "test-etag",
+      kind: "calendar#event",
+    },
+  ],
+};
+
+describe("CalendarSubscriptionService", () => {
+  let service: CalendarSubscriptionService;
+  let mockAdapterFactory: AdapterFactory;
+  let mockSelectedCalendarRepository: ISelectedCalendarRepository;
+  let mockFeaturesRepository: FeaturesRepository;
+  let mockCalendarCacheEventService: CalendarCacheEventService;
+  let mockCalendarSyncService: CalendarSyncService;
+  let mockAdapter: {
+    subscribe: ReturnType<typeof vi.fn>;
+    unsubscribe: ReturnType<typeof vi.fn>;
+    validate: ReturnType<typeof vi.fn>;
+    extractChannelId: ReturnType<typeof vi.fn>;
+    fetchEvents: ReturnType<typeof vi.fn>;
+  };
+
+  beforeEach(async () => {
+    mockAdapter = {
+      subscribe: vi.fn().mockResolvedValue(mockSubscriptionResult),
+      unsubscribe: vi.fn().mockResolvedValue(undefined),
+      validate: vi.fn().mockResolvedValue(true),
+      extractChannelId: vi.fn().mockResolvedValue("test-channel-id"),
+      fetchEvents: vi.fn().mockResolvedValue(mockEvents),
+    };
+
+    mockAdapterFactory = {
+      get: vi.fn().mockReturnValue(mockAdapter),
+      getProviders: vi.fn().mockReturnValue(["google_calendar", "office365_calendar"]),
+    };
+
+    mockSelectedCalendarRepository = {
+      findByIdWithCredentials: vi.fn().mockResolvedValue(mockSelectedCalendar),
+      findByChannelId: vi.fn().mockResolvedValue(mockSelectedCalendar),
+      findNextSubscriptionBatch: vi.fn().mockResolvedValue([mockSelectedCalendar]),
+      updateSyncStatus: vi.fn().mockResolvedValue(mockSelectedCalendar),
+      updateSubscription: vi.fn().mockResolvedValue(mockSelectedCalendar),
+    };
+
+    mockFeaturesRepository = {
+      checkIfFeatureIsEnabledGlobally: vi.fn().mockResolvedValue(true),
+      checkIfUserHasFeature: vi.fn().mockResolvedValue(true),
+    };
+
+    mockCalendarCacheEventService = {
+      handleEvents: vi.fn().mockResolvedValue(undefined),
+      cleanupCache: vi.fn().mockResolvedValue(undefined),
+      cleanupStaleCache: vi.fn().mockResolvedValue(undefined),
+    };
+
+    mockCalendarSyncService = {
+      handleEvents: vi.fn().mockResolvedValue(undefined),
+    };
+
+    service = new CalendarSubscriptionService({
+      adapterFactory: mockAdapterFactory,
+      selectedCalendarRepository: mockSelectedCalendarRepository,
+      featuresRepository: mockFeaturesRepository,
+      calendarCacheEventService: mockCalendarCacheEventService,
+      calendarSyncService: mockCalendarSyncService,
+    });
+
+    const { getCredentialForCalendarCache } = await import("../__mocks__/delegationCredential");
+    getCredentialForCalendarCache.mockResolvedValue(mockCredential);
+  });
+
+  describe("subscribe", () => {
+    test("should successfully subscribe to a calendar", async () => {
+      await service.subscribe("test-calendar-id");
+
+      expect(mockSelectedCalendarRepository.findByIdWithCredentials).toHaveBeenCalledWith("test-calendar-id");
+      expect(mockAdapterFactory.get).toHaveBeenCalledWith("google_calendar");
+      expect(mockAdapter.subscribe).toHaveBeenCalledWith(mockSelectedCalendar, mockCredential);
+      expect(mockSelectedCalendarRepository.updateSubscription).toHaveBeenCalledWith("test-calendar-id", {
+        channelId: "test-channel-id",
+        channelResourceId: "test-resource-id",
+        channelResourceUri: "test-resource-uri",
+        channelKind: "google_calendar",
+        channelExpiration: mockSubscriptionResult.expiration,
+        syncSubscribedAt: expect.any(Date),
+      });
+    });
+
+    test("should return early if selected calendar not found", async () => {
+      mockSelectedCalendarRepository.findByIdWithCredentials.mockResolvedValue(null);
+
+      await service.subscribe("non-existent-id");
+
+      expect(mockAdapter.subscribe).not.toHaveBeenCalled();
+      expect(mockSelectedCalendarRepository.updateSubscription).not.toHaveBeenCalled();
+    });
+
+    test("should return early if selected calendar has no credentialId", async () => {
+      mockSelectedCalendarRepository.findByIdWithCredentials.mockResolvedValue({
+        ...mockSelectedCalendar,
+        credentialId: null,
+      });
+
+      await service.subscribe("test-calendar-id");
+
+      expect(mockAdapter.subscribe).not.toHaveBeenCalled();
+      expect(mockSelectedCalendarRepository.updateSubscription).not.toHaveBeenCalled();
+    });
+  });
+
+  describe("unsubscribe", () => {
+    test("should successfully unsubscribe from a calendar", async () => {
+      mockFeaturesRepository.checkIfFeatureIsEnabledGlobally.mockResolvedValue(true);
+
+      await service.unsubscribe("test-calendar-id");
+
+      expect(mockSelectedCalendarRepository.findByIdWithCredentials).toHaveBeenCalledWith("test-calendar-id");
+      expect(mockAdapter.unsubscribe).toHaveBeenCalledWith(mockSelectedCalendar, mockCredential);
+      expect(mockSelectedCalendarRepository.updateSubscription).toHaveBeenCalledWith("test-calendar-id", {
+        syncSubscribedAt: null,
+      });
+      expect(mockCalendarCacheEventService.cleanupCache).toHaveBeenCalledWith(mockSelectedCalendar);
+    });
+
+    test("should not cleanup cache if cache is disabled", async () => {
+      mockFeaturesRepository.checkIfFeatureIsEnabledGlobally.mockResolvedValue(false);
+
+      await service.unsubscribe("test-calendar-id");
+
+      expect(mockCalendarCacheEventService.cleanupCache).not.toHaveBeenCalled();
+    });
+
+    test("should return early if selected calendar not found", async () => {
+      mockSelectedCalendarRepository.findByIdWithCredentials.mockResolvedValue(null);
+
+      await service.unsubscribe("non-existent-id");
+
+      expect(mockAdapter.unsubscribe).not.toHaveBeenCalled();
+    });
+  });
+
+  describe("processWebhook", () => {
+    test("should successfully process a valid webhook", async () => {
+      const mockRequest = new Request("http://example.com");
+
+      await service.processWebhook("google_calendar", mockRequest);
+
+      expect(mockAdapter.validate).toHaveBeenCalledWith(mockRequest);
+      expect(mockAdapter.extractChannelId).toHaveBeenCalledWith(mockRequest);
+      expect(mockSelectedCalendarRepository.findByChannelId).toHaveBeenCalledWith("test-channel-id");
+    });
+
+    test("should throw error for invalid webhook", async () => {
+      const mockRequest = new Request("http://example.com");
+      mockAdapter.validate.mockResolvedValue(false);
+
+      await expect(service.processWebhook("google_calendar", mockRequest)).rejects.toThrow(
+        "Invalid webhook request"
+      );
+    });
+
+    test("should throw error for missing channel ID", async () => {
+      const mockRequest = new Request("http://example.com");
+      mockAdapter.extractChannelId.mockResolvedValue(null);
+
+      await expect(service.processWebhook("google_calendar", mockRequest)).rejects.toThrow(
+        "Missing channel ID in webhook"
+      );
+    });
+
+    test("should return null for old subscription", async () => {
+      const mockRequest = new Request("http://example.com");
+      mockSelectedCalendarRepository.findByChannelId.mockResolvedValue(null);
+
+      const _result = await service.processWebhook("google_calendar", mockRequest);
+
+      expect(_result).toBeNull();
+    });
+  });
+
+  describe("processEvents", () => {
+    test("should process events when both cache and sync are enabled", async () => {
+      mockFeaturesRepository.checkIfFeatureIsEnabledGlobally
+        .mockResolvedValueOnce(true)
+        .mockResolvedValueOnce(true);
+      mockFeaturesRepository.checkIfUserHasFeature.mockResolvedValue(true);
+
+      await service.processEvents(mockSelectedCalendar);
+
+      expect(mockAdapter.fetchEvents).toHaveBeenCalledWith(mockSelectedCalendar, mockCredential);
+      expect(mockSelectedCalendarRepository.updateSyncStatus).toHaveBeenCalledWith(mockSelectedCalendar.id, {
+        syncToken: "new-sync-token",
+        syncedAt: expect.any(Date),
+        syncErrorAt: null,
+        syncErrorCount: 0,
+      });
+      expect(mockCalendarCacheEventService.handleEvents).toHaveBeenCalledWith(
+        mockSelectedCalendar,
+        mockEvents.items
+      );
+      expect(mockCalendarSyncService.handleEvents).toHaveBeenCalledWith(
+        mockSelectedCalendar,
+        mockEvents.items
+      );
+    });
+
+    test("should not process cache when cache is disabled globally", async () => {
+      mockFeaturesRepository.checkIfFeatureIsEnabledGlobally
+        .mockResolvedValueOnce(false)
+        .mockResolvedValueOnce(true);
+      mockFeaturesRepository.checkIfUserHasFeature.mockResolvedValue(true);
+
+      await service.processEvents(mockSelectedCalendar);
+
+      expect(mockCalendarCacheEventService.handleEvents).not.toHaveBeenCalled();
+      expect(mockCalendarSyncService.handleEvents).toHaveBeenCalled();
+    });
+
+    test("should not process cache when cache is disabled for user", async () => {
+      mockFeaturesRepository.checkIfFeatureIsEnabledGlobally
+        .mockResolvedValueOnce(true)
+        .mockResolvedValueOnce(true);
+      mockFeaturesRepository.checkIfUserHasFeature.mockResolvedValue(false);
+
+      await service.processEvents(mockSelectedCalendar);
+
+      expect(mockCalendarCacheEventService.handleEvents).not.toHaveBeenCalled();
+      expect(mockCalendarSyncService.handleEvents).toHaveBeenCalled();
+    });
+
+    test("should return early when both cache and sync are disabled", async () => {
+      mockFeaturesRepository.checkIfFeatureIsEnabledGlobally
+        .mockResolvedValueOnce(false)
+        .mockResolvedValueOnce(false);
+
+      await service.processEvents(mockSelectedCalendar);
+
+      expect(mockAdapter.fetchEvents).not.toHaveBeenCalled();
+      expect(mockCalendarCacheEventService.handleEvents).not.toHaveBeenCalled();
+      expect(mockCalendarSyncService.handleEvents).not.toHaveBeenCalled();
+    });
+
+    test("should handle API errors and update sync status", async () => {
+      mockFeaturesRepository.checkIfFeatureIsEnabledGlobally
+        .mockResolvedValueOnce(true)
+        .mockResolvedValueOnce(true);
+      mockFeaturesRepository.checkIfUserHasFeature.mockResolvedValue(true);
+
+      const apiError = new Error("API Error");
+      mockAdapter.fetchEvents.mockRejectedValue(apiError);
+
+      await expect(service.processEvents(mockSelectedCalendar)).rejects.toThrow("API Error");
+
+      expect(mockSelectedCalendarRepository.updateSyncStatus).toHaveBeenCalledWith(mockSelectedCalendar.id, {
+        syncErrorAt: expect.any(Date),
+        syncErrorCount: {
+          increment: 1,
+        },
+      });
+    });
+
+    test("should return early when no events are fetched", async () => {
+      mockFeaturesRepository.checkIfFeatureIsEnabledGlobally
+        .mockResolvedValueOnce(true)
+        .mockResolvedValueOnce(true);
+      mockFeaturesRepository.checkIfUserHasFeature.mockResolvedValue(true);
+
+      mockAdapter.fetchEvents.mockResolvedValue({
+        ...mockEvents,
+        items: [],
+      });
+
+      await service.processEvents(mockSelectedCalendar);
+
+      expect(mockCalendarCacheEventService.handleEvents).not.toHaveBeenCalled();
+      expect(mockCalendarSyncService.handleEvents).not.toHaveBeenCalled();
+    });
+
+    test("should return early when selected calendar has no credentialId", async () => {
+      const calendarWithoutCredential = {
+        ...mockSelectedCalendar,
+        credentialId: null,
+      };
+
+      await service.processEvents(calendarWithoutCredential);
+
+      expect(mockAdapter.fetchEvents).not.toHaveBeenCalled();
+    });
+  });
+
+  describe("checkForNewSubscriptions", () => {
+    test("should process new subscriptions", async () => {
+      const subscribeSpy = vi.spyOn(service, "subscribe").mockResolvedValue(undefined);
+
+      await service.checkForNewSubscriptions();
+
+      expect(mockSelectedCalendarRepository.findNextSubscriptionBatch).toHaveBeenCalledWith({
+        take: 100,
+        integrations: ["google_calendar", "office365_calendar"],
+      });
+      expect(subscribeSpy).toHaveBeenCalledWith(mockSelectedCalendar.id);
+    });
+  });
+
+  describe("feature flag methods", () => {
+    test("isCacheEnabled should check global cache feature", async () => {
+      mockFeaturesRepository.checkIfFeatureIsEnabledGlobally.mockResolvedValue(true);
+
+      const result = await service.isCacheEnabled();
+
+      expect(result).toBe(true);
+      expect(mockFeaturesRepository.checkIfFeatureIsEnabledGlobally).toHaveBeenCalledWith(
+        "calendar-subscription-cache"
+      );
+    });
+
+    test("isCacheEnabledForUser should check user cache feature", async () => {
+      mockFeaturesRepository.checkIfUserHasFeature.mockResolvedValue(true);
+
+      const result = await service.isCacheEnabledForUser(1);
+
+      expect(result).toBe(true);
+      expect(mockFeaturesRepository.checkIfUserHasFeature).toHaveBeenCalledWith(
+        1,
+        "calendar-subscription-cache"
+      );
+    });
+
+    test("isSyncEnabled should check global sync feature", async () => {
+      mockFeaturesRepository.checkIfFeatureIsEnabledGlobally.mockResolvedValue(true);
+
+      const result = await service.isSyncEnabled();
+
+      expect(result).toBe(true);
+      expect(mockFeaturesRepository.checkIfFeatureIsEnabledGlobally).toHaveBeenCalledWith(
+        "calendar-subscription-sync"
+      );
+    });
+  });
+});
@@ -0,0 +1,41 @@
+import type { CalendarCacheEvent } from "@calcom/prisma/client";
+
+/**
+ * Repository to handle calendar cache
+ */
+export interface ICalendarCacheEventRepository {
+  /**
+   * Upserts many events
+   * @param events the list of events to upsert
+   */
+  upsertMany(events: Partial<CalendarCacheEvent>[]): Promise<unknown>;
+
+  /**
+   * Deletes many events
+   * @param events the list of events to delete
+   */
+  deleteMany(events: Pick<CalendarCacheEvent, "externalId" | "selectedCalendarId">[]): Promise<unknown>;
+
+  /**
+   * Deletes all events for a selected calendar
+   * @param selectedCalendarId the id of the calendar
+   */
+  deleteAllBySelectedCalendarId(selectedCalendarId: string): Promise<unknown>;
+
+  /**
+   * Deletes all stale events
+   */
+  deleteStale(): Promise<unknown>;
+
+  /**
+   *
+   * @param selectedCalendarId
+   * @param start
+   * @param end
+   */
+  findAllBySelectedCalendarIdsBetween(
+    selectedCalendarId: string[],
+    start: Date,
+    end: Date
+  ): Promise<Pick<CalendarCacheEvent, "start" | "end" | "timeZone">[]>;
+}
@@ -0,0 +1,92 @@
+import type { ICalendarCacheEventRepository } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventRepository.interface";
+import type { PrismaClient } from "@calcom/prisma";
+import type { CalendarCacheEvent } from "@calcom/prisma/client";
+
+export class CalendarCacheEventRepository implements ICalendarCacheEventRepository {
+  constructor(private prismaClient: PrismaClient) {}
+
+  async findAllBySelectedCalendarIdsBetween(
+    selectedCalendarId: string[],
+    start: Date,
+    end: Date
+  ): Promise<Pick<CalendarCacheEvent, "start" | "end" | "timeZone">[]> {
+    return this.prismaClient.calendarCacheEvent.findMany({
+      where: {
+        selectedCalendarId: {
+          in: selectedCalendarId,
+        },
+        AND: [{ start: { lt: end } }, { end: { gt: start } }],
+      },
+      select: {
+        start: true,
+        end: true,
+        timeZone: true,
+      },
+    });
+  }
+
+  async upsertMany(events: CalendarCacheEvent[]) {
+    if (events.length === 0) {
+      return;
+    }
+    // lack of upsertMany in prisma
+    return Promise.allSettled(
+      events.map((event) => {
+        return this.prismaClient.calendarCacheEvent.upsert({
+          where: {
+            selectedCalendarId_externalId: {
+              externalId: event.externalId,
+              selectedCalendarId: event.selectedCalendarId,
+            },
+          },
+          update: {
+            start: event.start,
+            end: event.end,
+            summary: event.summary,
+            description: event.description,
+            location: event.location,
+            isAllDay: event.isAllDay,
+            timeZone: event.timeZone,
+          },
+          create: event,
+        });
+      })
+    );
+  }
+
+  async deleteMany(events: Pick<CalendarCacheEvent, "externalId" | "selectedCalendarId">[]) {
+    // Only delete events with externalId and selectedCalendarId
+    const conditions = events.filter((c) => c.externalId && c.selectedCalendarId);
+    if (conditions.length === 0) {
+      return;
+    }
+
+    return this.prismaClient.calendarCacheEvent.deleteMany({
+      where: {
+        OR: conditions,
+      },
+    });
+  }
+
+  async deleteAllBySelectedCalendarId(selectedCalendarId: string) {
+    if (!selectedCalendarId) {
+      return;
+    }
+
+    return this.prismaClient.calendarCacheEvent.deleteMany({
+      where: {
+        selectedCalendarId,
+      },
+    });
+  }
+
+  async deleteStale() {
+    return this.prismaClient.calendarCacheEvent.deleteMany({
+      where: {
+        end: {
+          lte: new Date(),
+        },
+      },
+    });
+  }
+}
@@ -0,0 +1,99 @@
+import type { CalendarSubscriptionEventItem } from "@calcom/features/calendar-subscription/lib/CalendarSubscriptionPort.interface";
+import type { ICalendarCacheEventRepository } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventRepository.interface";
+import logger from "@calcom/lib/logger";
+import type { CalendarCacheEvent, SelectedCalendar } from "@calcom/prisma/client";
+
+const log = logger.getSubLogger({ prefix: ["CalendarCacheEventService"] });
+
+/**
+ * Service to handle calendar cache
+ */
+export class CalendarCacheEventService {
+  constructor(
+    private deps: {
+      calendarCacheEventRepository: ICalendarCacheEventRepository;
+    }
+  ) {}
+
+  /**
+   * Handle calendar events from provider and update the cache
+   *
+   * @param selectedCalendar
+   * @param calendarSubscriptionEvents
+   */
+  async handleEvents(
+    selectedCalendar: SelectedCalendar,
+    calendarSubscriptionEvents: CalendarSubscriptionEventItem[]
+  ): Promise<void> {
+    log.debug("handleEvents", { count: calendarSubscriptionEvents.length });
+    const toUpsert: Partial<CalendarCacheEvent>[] = [];
+    const toDelete: Pick<CalendarCacheEvent, "externalId" | "selectedCalendarId">[] = [];
+
+    for (const event of calendarSubscriptionEvents) {
+      // not storing free or cancelled events
+      if (event.busy && event.status !== "cancelled") {
+        toUpsert.push({
+          externalId: event.id,
+          selectedCalendarId: selectedCalendar.id,
+          start: event.start,
+          end: event.end,
+          summary: event.summary,
+          description: event.description,
+          location: event.location,
+          isAllDay: event.isAllDay,
+          timeZone: event.timeZone,
+          originalStartTime: event.originalStartDate,
+          recurringEventId: event.recurringEventId,
+          externalEtag: event.etag || "",
+          externalCreatedAt: event.createdAt,
+          externalUpdatedAt: event.updatedAt,
+        });
+      } else {
+        toDelete.push({
+          selectedCalendarId: selectedCalendar.id,
+          externalId: event.id,
+        });
+      }
+    }
+
+    log.info("handleEvents: applying changes to the database", {
+      received: calendarSubscriptionEvents.length,
+      toUpsert: toUpsert.length,
+      toDelete: toDelete.length,
+    });
+    await Promise.all([
+      this.deps.calendarCacheEventRepository.deleteMany(toDelete),
+      this.deps.calendarCacheEventRepository.upsertMany(toUpsert),
+    ]);
+  }
+
+  /**
+   * Removes all events from the cache
+   *
+   * @param selectedCalendar calendar to cleanup
+   */
+  async cleanupCache(selectedCalendar: SelectedCalendar): Promise<void> {
+    log.debug("cleanupCache", { selectedCalendarId: selectedCalendar.id });
+    await this.deps.calendarCacheEventRepository.deleteAllBySelectedCalendarId(selectedCalendar.id);
+  }
+
+  /**
+   * Removes stale events from the cache
+   */
+  async cleanupStaleCache(): Promise<void> {
+    log.debug("cleanupStaleCache");
+    await this.deps.calendarCacheEventRepository.deleteStale();
+  }
+
+  /**
+   * Checks if the app is supported
+   *
+   * @param type
+   * @returns
+   */
+  static isCalendarTypeSupported(type: string | null): boolean {
+    if (!type) return false;
+    // return ["google_calendar", "office365_calendar"].includes(type);
+    return ["google_calendar"].includes(type);
+  }
+}
@@ -0,0 +1,132 @@
+import type { ICalendarCacheEventRepository } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventRepository.interface";
+import logger from "@calcom/lib/logger";
+import type {
+  Calendar,
+  CalendarEvent,
+  CalendarServiceEvent,
+  EventBusyDate,
+  IntegrationCalendar,
+  NewCalendarEventType,
+  SelectedCalendarEventTypeIds,
+} from "@calcom/types/Calendar";
+
+const log = logger.getSubLogger({ prefix: ["CachedCalendarWrapper"] });
+
+/**
+ * A wrapper to load cache from database and cache it.
+ *
+ * @see Calendar
+ */
+export class CalendarCacheWrapper implements Calendar {
+  constructor(
+    private deps: {
+      originalCalendar: Calendar;
+      calendarCacheEventRepository: ICalendarCacheEventRepository;
+    }
+  ) {}
+
+  getCredentialId?(): number {
+    return this.deps.originalCalendar.getCredentialId ? this.deps.originalCalendar.getCredentialId() : -1;
+  }
+
+  createEvent(
+    event: CalendarServiceEvent,
+    credentialId: number,
+    externalCalendarId?: string
+  ): Promise<NewCalendarEventType> {
+    return this.deps.originalCalendar.createEvent(event, credentialId, externalCalendarId);
+  }
+
+  updateEvent(
+    uid: string,
+    event: CalendarServiceEvent,
+    externalCalendarId?: string | null
+  ): Promise<NewCalendarEventType | NewCalendarEventType[]> {
+    return this.deps.originalCalendar.updateEvent(uid, event, externalCalendarId);
+  }
+
+  deleteEvent(uid: string, event: CalendarEvent, externalCalendarId?: string | null): Promise<unknown> {
+    return this.deps.originalCalendar.deleteEvent(uid, event, externalCalendarId);
+  }
+
+  /**
+   * Override this method to use cache
+   *
+   * @param dateFrom
+   * @param dateTo
+   * @param selectedCalendars
+   * @param shouldServeCache
+   */
+  async getAvailability(
+    dateFrom: string,
+    dateTo: string,
+    selectedCalendars: IntegrationCalendar[],
+    shouldServeCache?: boolean
+    // _fallbackToPrimary?: boolean
+  ): Promise<EventBusyDate[]> {
+    if (!shouldServeCache) {
+      return this.deps.originalCalendar.getAvailability(dateFrom, dateTo, selectedCalendars);
+    }
+
+    log.debug("getAvailability from cache", { dateFrom, dateTo, selectedCalendars });
+    const selectedCalendarIds = selectedCalendars.map((e) => e.id).filter((id): id is string => Boolean(id));
+    if (!selectedCalendarIds.length) {
+      return Promise.resolve([]);
+    }
+    return this.deps.calendarCacheEventRepository.findAllBySelectedCalendarIdsBetween(
+      selectedCalendarIds,
+      new Date(dateFrom),
+      new Date(dateTo)
+    );
+  }
+
+  /**
+   * Override this method to use cache
+   *
+   * @param dateFrom
+   * @param dateTo
+   * @param selectedCalendars
+   * @returns
+   */
+  async getAvailabilityWithTimeZones?(
+    dateFrom: string,
+    dateTo: string,
+    selectedCalendars: IntegrationCalendar[]
+    // _fallbackToPrimary?: boolean
+  ): Promise<{ start: Date | string; end: Date | string; timeZone: string }[]> {
+    log.debug("getAvailabilityWithTimeZones from cache", { dateFrom, dateTo, selectedCalendars });
+    const selectedCalendarIds = selectedCalendars.map((e) => e.id).filter((id): id is string => Boolean(id));
+    const result = await this.deps.calendarCacheEventRepository.findAllBySelectedCalendarIdsBetween(
+      selectedCalendarIds,
+      new Date(dateFrom),
+      new Date(dateTo)
+    );
+    return result.map(({ start, end, timeZone }) => ({ start, end, timeZone: timeZone || "UTC" }));
+  }
+
+  fetchAvailabilityAndSetCache?(selectedCalendars: IntegrationCalendar[]): Promise<unknown> {
+    return this.deps.originalCalendar.fetchAvailabilityAndSetCache?.(selectedCalendars) || Promise.resolve();
+  }
+
+  listCalendars(event?: CalendarEvent): Promise<IntegrationCalendar[]> {
+    return this.deps.originalCalendar.listCalendars(event);
+  }
+
+  testDelegationCredentialSetup?(): Promise<boolean> {
+    return this.deps.originalCalendar.testDelegationCredentialSetup?.() || Promise.resolve(false);
+  }
+
+  watchCalendar?(options: {
+    calendarId: string;
+    eventTypeIds: SelectedCalendarEventTypeIds;
+  }): Promise<unknown> {
+    return this.deps.originalCalendar.watchCalendar?.(options) || Promise.resolve();
+  }
+
+  unwatchCalendar?(options: {
+    calendarId: string;
+    eventTypeIds: SelectedCalendarEventTypeIds;
+  }): Promise<void> {
+    return this.deps.originalCalendar.unwatchCalendar?.(options) || Promise.resolve();
+  }
+}
@@ -0,0 +1,249 @@
+import { describe, test, expect, vi, beforeEach } from "vitest";
+
+import type { PrismaClient } from "@calcom/prisma";
+import type { CalendarCacheEvent } from "@calcom/prisma/client";
+
+import { CalendarCacheEventRepository } from "../CalendarCacheEventRepository";
+
+const mockPrismaClient = {
+  calendarCacheEvent: {
+    findMany: vi.fn(),
+    upsert: vi.fn(),
+    deleteMany: vi.fn(),
+  },
+} as unknown as PrismaClient;
+
+const mockCalendarCacheEvent: CalendarCacheEvent = {
+  id: "test-id",
+  iCalUID: null,
+  iCalSequence: 0,
+  selectedCalendarId: "test-calendar-id",
+  externalId: "external-event-id",
+  start: new Date("2023-12-01T10:00:00Z"),
+  end: new Date("2023-12-01T11:00:00Z"),
+  status: "confirmed",
+  summary: "Test Event",
+  description: "Test Description",
+  location: "Test Location",
+  isAllDay: false,
+  timeZone: "UTC",
+  originalStartTime: null,
+  recurringEventId: null,
+  externalEtag: "test-etag",
+  externalCreatedAt: new Date("2023-12-01T09:00:00Z"),
+  externalUpdatedAt: new Date("2023-12-01T09:30:00Z"),
+  createdAt: new Date("2023-12-01T09:00:00Z"),
+  updatedAt: new Date("2023-12-01T09:30:00Z"),
+};
+
+describe("CalendarCacheEventRepository", () => {
+  let repository: CalendarCacheEventRepository;
+
+  beforeEach(() => {
+    repository = new CalendarCacheEventRepository(mockPrismaClient);
+    vi.clearAllMocks();
+  });
+
+  describe("findAllBySelectedCalendarIdsBetween", () => {
+    test("should find events by selected calendar IDs and date range", async () => {
+      const mockEvents = [
+        {
+          start: new Date("2023-12-01T10:00:00Z"),
+          end: new Date("2023-12-01T11:00:00Z"),
+          timeZone: "UTC",
+        },
+      ] as unknown as CalendarCacheEvent[];
+
+      vi.mocked(mockPrismaClient.calendarCacheEvent.findMany).mockResolvedValue(mockEvents);
+
+      const result = await repository.findAllBySelectedCalendarIdsBetween(
+        ["calendar-1", "calendar-2"],
+        new Date("2023-12-01T00:00:00Z"),
+        new Date("2023-12-01T23:59:59Z")
+      );
+
+      expect(mockPrismaClient.calendarCacheEvent.findMany).toHaveBeenCalledWith({
+        where: {
+          selectedCalendarId: {
+            in: ["calendar-1", "calendar-2"],
+          },
+          AND: [
+            { start: { lt: new Date("2023-12-01T23:59:59Z") } },
+            { end: { gt: new Date("2023-12-01T00:00:00Z") } },
+          ],
+        },
+        select: {
+          start: true,
+          end: true,
+          timeZone: true,
+        },
+      });
+
+      expect(result).toEqual(mockEvents);
+    });
+  });
+
+  describe("upsertMany", () => {
+    test("should upsert multiple events", async () => {
+      const events = [mockCalendarCacheEvent];
+      vi.mocked(mockPrismaClient.calendarCacheEvent.upsert).mockResolvedValue(mockCalendarCacheEvent);
+
+      await repository.upsertMany(events);
+
+      expect(mockPrismaClient.calendarCacheEvent.upsert).toHaveBeenCalledWith({
+        where: {
+          selectedCalendarId_externalId: {
+            externalId: "external-event-id",
+            selectedCalendarId: "test-calendar-id",
+          },
+        },
+        update: {
+          start: mockCalendarCacheEvent.start,
+          end: mockCalendarCacheEvent.end,
+          summary: mockCalendarCacheEvent.summary,
+          description: mockCalendarCacheEvent.description,
+          location: mockCalendarCacheEvent.location,
+          isAllDay: mockCalendarCacheEvent.isAllDay,
+          timeZone: mockCalendarCacheEvent.timeZone,
+        },
+        create: mockCalendarCacheEvent,
+      });
+    });
+
+    test("should return early when events array is empty", async () => {
+      const result = await repository.upsertMany([]);
+
+      expect(mockPrismaClient.calendarCacheEvent.upsert).not.toHaveBeenCalled();
+      expect(result).toBeUndefined();
+    });
+
+    test("should handle multiple events", async () => {
+      const events = [
+        mockCalendarCacheEvent,
+        {
+          ...mockCalendarCacheEvent,
+          id: "test-id-2",
+          externalId: "external-event-id-2",
+        },
+      ];
+
+      vi.mocked(mockPrismaClient.calendarCacheEvent.upsert).mockResolvedValue(mockCalendarCacheEvent);
+
+      await repository.upsertMany(events);
+
+      expect(mockPrismaClient.calendarCacheEvent.upsert).toHaveBeenCalledTimes(2);
+    });
+  });
+
+  describe("deleteMany", () => {
+    test("should delete multiple events", async () => {
+      const eventsToDelete = [
+        {
+          externalId: "external-event-id-1",
+          selectedCalendarId: "test-calendar-id",
+        },
+        {
+          externalId: "external-event-id-2",
+          selectedCalendarId: "test-calendar-id",
+        },
+      ];
+
+      vi.mocked(mockPrismaClient.calendarCacheEvent.deleteMany).mockResolvedValue({ count: 2 });
+
+      await repository.deleteMany(eventsToDelete);
+
+      expect(mockPrismaClient.calendarCacheEvent.deleteMany).toHaveBeenCalledWith({
+        where: {
+          OR: eventsToDelete,
+        },
+      });
+    });
+
+    test("should return early when events array is empty", async () => {
+      const result = await repository.deleteMany([]);
+
+      expect(mockPrismaClient.calendarCacheEvent.deleteMany).not.toHaveBeenCalled();
+      expect(result).toBeUndefined();
+    });
+
+    test("should filter out events without externalId or selectedCalendarId", async () => {
+      const eventsToDelete = [
+        {
+          externalId: "external-event-id-1",
+          selectedCalendarId: "test-calendar-id",
+        },
+        {
+          externalId: "",
+          selectedCalendarId: "test-calendar-id",
+        },
+        {
+          externalId: "external-event-id-3",
+          selectedCalendarId: "",
+        },
+      ];
+
+      vi.mocked(mockPrismaClient.calendarCacheEvent.deleteMany).mockResolvedValue({ count: 1 });
+
+      await repository.deleteMany(eventsToDelete);
+
+      expect(mockPrismaClient.calendarCacheEvent.deleteMany).toHaveBeenCalledWith({
+        where: {
+          OR: [
+            {
+              externalId: "external-event-id-1",
+              selectedCalendarId: "test-calendar-id",
+            },
+          ],
+        },
+      });
+    });
+
+    test("should return early when no valid events to delete", async () => {
+      const eventsToDelete = [
+        {
+          externalId: "",
+          selectedCalendarId: "test-calendar-id",
+        },
+        {
+          externalId: "external-event-id",
+          selectedCalendarId: "",
+        },
+      ];
+
+      const result = await repository.deleteMany(eventsToDelete);
+
+      expect(mockPrismaClient.calendarCacheEvent.deleteMany).not.toHaveBeenCalled();
+      expect(result).toBeUndefined();
+    });
+  });
+
+  describe("deleteAllBySelectedCalendarId", () => {
+    test("should delete all events for a selected calendar", async () => {
+      vi.mocked(mockPrismaClient.calendarCacheEvent.deleteMany).mockResolvedValue({ count: 5 });
+
+      await repository.deleteAllBySelectedCalendarId("test-calendar-id");
+
+      expect(mockPrismaClient.calendarCacheEvent.deleteMany).toHaveBeenCalledWith({
+        where: {
+          selectedCalendarId: "test-calendar-id",
+        },
+      });
+    });
+  });
+
+  describe("deleteStale", () => {
+    test("should delete stale events", async () => {
+      vi.mocked(mockPrismaClient.calendarCacheEvent.deleteMany).mockResolvedValue({ count: 3 });
+
+      await repository.deleteStale();
+
+      expect(mockPrismaClient.calendarCacheEvent.deleteMany).toHaveBeenCalledWith({
+        where: {
+          end: {
+            lte: expect.any(Date),
+          },
+        },
+      });
+    });
+  });
+});
@@ -0,0 +1,354 @@
+import { describe, test, expect, vi, beforeEach } from "vitest";
+
+import type { CalendarSubscriptionEventItem } from "@calcom/features/calendar-subscription/lib/CalendarSubscriptionPort.interface";
+import type { ICalendarCacheEventRepository } from "@calcom/features/calendar-subscription/lib/cache/CalendarCacheEventRepository.interface";
+import type { SelectedCalendar } from "@calcom/prisma/client";
+
+import { CalendarCacheEventService } from "../CalendarCacheEventService";
+
+const mockSelectedCalendar: SelectedCalendar = {
+  id: "test-calendar-id",
+  userId: 1,
+  credentialId: 1,
+  integration: "google_calendar",
+  externalId: "test@example.com",
+  eventTypeId: null,
+  delegationCredentialId: null,
+  domainWideDelegationCredentialId: null,
+  googleChannelId: null,
+  googleChannelKind: null,
+  googleChannelResourceId: null,
+  googleChannelResourceUri: null,
+  googleChannelExpiration: null,
+  error: null,
+  lastErrorAt: null,
+  watchAttempts: 0,
+  maxAttempts: 3,
+  unwatchAttempts: 0,
+  createdAt: new Date(),
+  updatedAt: new Date(),
+  channelId: "test-channel-id",
+  channelKind: "web_hook",
+  channelResourceId: "test-resource-id",
+  channelResourceUri: "test-resource-uri",
+  channelExpiration: new Date(Date.now() + 86400000),
+  syncSubscribedAt: new Date(),
+  syncToken: "test-sync-token",
+  syncedAt: new Date(),
+  syncErrorAt: null,
+  syncErrorCount: 0,
+};
+
+describe("CalendarCacheEventService", () => {
+  let service: CalendarCacheEventService;
+  let mockRepository: ICalendarCacheEventRepository;
+
+  beforeEach(() => {
+    mockRepository = {
+      upsertMany: vi.fn().mockResolvedValue(undefined),
+      deleteMany: vi.fn().mockResolvedValue(undefined),
+      deleteAllBySelectedCalendarId: vi.fn().mockResolvedValue(undefined),
+      deleteStale: vi.fn().mockResolvedValue(undefined),
+      findAllBySelectedCalendarIdsBetween: vi.fn().mockResolvedValue([]),
+    };
+
+    service = new CalendarCacheEventService({
+      calendarCacheEventRepository: mockRepository,
+    });
+  });
+
+  describe("handleEvents", () => {
+    test("should process busy events and store them in cache", async () => {
+      const events: CalendarSubscriptionEventItem[] = [
+        {
+          id: "event-1",
+          iCalUID: "event-1@cal.com",
+          start: new Date("2023-12-01T10:00:00Z"),
+          end: new Date("2023-12-01T11:00:00Z"),
+          busy: true,
+          summary: "Test Event",
+          description: "Test Description",
+          location: "Test Location",
+          status: "confirmed",
+          isAllDay: false,
+          timeZone: "UTC",
+          recurringEventId: null,
+          originalStartDate: null,
+          createdAt: new Date("2023-12-01T09:00:00Z"),
+          updatedAt: new Date("2023-12-01T09:30:00Z"),
+          etag: "test-etag",
+          kind: "calendar#event",
+        },
+      ];
+
+      await service.handleEvents(mockSelectedCalendar, events);
+
+      expect(mockRepository.upsertMany).toHaveBeenCalledWith([
+        {
+          externalId: "event-1",
+          selectedCalendarId: "test-calendar-id",
+          start: new Date("2023-12-01T10:00:00Z"),
+          end: new Date("2023-12-01T11:00:00Z"),
+          summary: "Test Event",
+          description: "Test Description",
+          location: "Test Location",
+          isAllDay: false,
+          timeZone: "UTC",
+          originalStartTime: null,
+          recurringEventId: null,
+          externalEtag: "test-etag",
+          externalCreatedAt: new Date("2023-12-01T09:00:00Z"),
+          externalUpdatedAt: new Date("2023-12-01T09:30:00Z"),
+        },
+      ]);
+      expect(mockRepository.deleteMany).toHaveBeenCalledWith([]);
+    });
+
+    test("should not store free events in cache", async () => {
+      const events: CalendarSubscriptionEventItem[] = [
+        {
+          id: "event-1",
+          iCalUID: "event-1@cal.com",
+          start: new Date("2023-12-01T10:00:00Z"),
+          end: new Date("2023-12-01T11:00:00Z"),
+          busy: false,
+          summary: "Free Event",
+          description: "Free Description",
+          location: "Free Location",
+          status: "confirmed",
+          isAllDay: false,
+          timeZone: "UTC",
+          recurringEventId: null,
+          originalStartDate: null,
+          createdAt: new Date("2023-12-01T09:00:00Z"),
+          updatedAt: new Date("2023-12-01T09:30:00Z"),
+          etag: "test-etag",
+          kind: "calendar#event",
+        },
+      ];
+
+      await service.handleEvents(mockSelectedCalendar, events);
+
+      expect(mockRepository.upsertMany).toHaveBeenCalledWith([]);
+      expect(mockRepository.deleteMany).toHaveBeenCalledWith([
+        {
+          selectedCalendarId: "test-calendar-id",
+          externalId: "event-1",
+        },
+      ]);
+    });
+
+    test("should delete cancelled events from cache", async () => {
+      const events: CalendarSubscriptionEventItem[] = [
+        {
+          id: "event-1",
+          iCalUID: "event-1@cal.com",
+          start: new Date("2023-12-01T10:00:00Z"),
+          end: new Date("2023-12-01T11:00:00Z"),
+          busy: true,
+          summary: "Cancelled Event",
+          description: "Cancelled Description",
+          location: "Cancelled Location",
+          status: "cancelled",
+          isAllDay: false,
+          timeZone: "UTC",
+          recurringEventId: null,
+          originalStartDate: null,
+          createdAt: new Date("2023-12-01T09:00:00Z"),
+          updatedAt: new Date("2023-12-01T09:30:00Z"),
+          etag: "test-etag",
+          kind: "calendar#event",
+        },
+      ];
+
+      await service.handleEvents(mockSelectedCalendar, events);
+
+      expect(mockRepository.upsertMany).toHaveBeenCalledWith([]);
+      expect(mockRepository.deleteMany).toHaveBeenCalledWith([
+        {
+          selectedCalendarId: "test-calendar-id",
+          externalId: "event-1",
+        },
+      ]);
+    });
+
+    test("should handle mixed event types correctly", async () => {
+      const events: CalendarSubscriptionEventItem[] = [
+        {
+          id: "event-1",
+          iCalUID: "event-1@cal.com",
+          start: new Date("2023-12-01T10:00:00Z"),
+          end: new Date("2023-12-01T11:00:00Z"),
+          busy: true,
+          summary: "Busy Event",
+          description: "Busy Description",
+          location: "Busy Location",
+          status: "confirmed",
+          isAllDay: false,
+          timeZone: "UTC",
+          recurringEventId: null,
+          originalStartDate: null,
+          createdAt: new Date("2023-12-01T09:00:00Z"),
+          updatedAt: new Date("2023-12-01T09:30:00Z"),
+          etag: "test-etag-1",
+          kind: "calendar#event",
+        },
+        {
+          id: "event-2",
+          iCalUID: "event-2@cal.com",
+          start: new Date("2023-12-01T12:00:00Z"),
+          end: new Date("2023-12-01T13:00:00Z"),
+          busy: false,
+          summary: "Free Event",
+          description: "Free Description",
+          location: "Free Location",
+          status: "confirmed",
+          isAllDay: false,
+          timeZone: "UTC",
+          recurringEventId: null,
+          originalStartDate: null,
+          createdAt: new Date("2023-12-01T11:00:00Z"),
+          updatedAt: new Date("2023-12-01T11:30:00Z"),
+          etag: "test-etag-2",
+          kind: "calendar#event",
+        },
+        {
+          id: "event-3",
+          iCalUID: "event-3@cal.com",
+          start: new Date("2023-12-01T14:00:00Z"),
+          end: new Date("2023-12-01T15:00:00Z"),
+          busy: true,
+          summary: "Cancelled Event",
+          description: "Cancelled Description",
+          location: "Cancelled Location",
+          status: "cancelled",
+          isAllDay: false,
+          timeZone: "UTC",
+          recurringEventId: null,
+          originalStartDate: null,
+          createdAt: new Date("2023-12-01T13:00:00Z"),
+          updatedAt: new Date("2023-12-01T13:30:00Z"),
+          etag: "test-etag-3",
+          kind: "calendar#event",
+        },
+      ];
+
+      await service.handleEvents(mockSelectedCalendar, events);
+
+      expect(mockRepository.upsertMany).toHaveBeenCalledWith([
+        {
+          externalId: "event-1",
+          selectedCalendarId: "test-calendar-id",
+          start: new Date("2023-12-01T10:00:00Z"),
+          end: new Date("2023-12-01T11:00:00Z"),
+          summary: "Busy Event",
+          description: "Busy Description",
+          location: "Busy Location",
+          isAllDay: false,
+          timeZone: "UTC",
+          originalStartTime: null,
+          recurringEventId: null,
+          externalEtag: "test-etag-1",
+          externalCreatedAt: new Date("2023-12-01T09:00:00Z"),
+          externalUpdatedAt: new Date("2023-12-01T09:30:00Z"),
+        },
+      ]);
+      expect(mockRepository.deleteMany).toHaveBeenCalledWith([
+        {
+          selectedCalendarId: "test-calendar-id",
+          externalId: "event-2",
+        },
+        {
+          selectedCalendarId: "test-calendar-id",
+          externalId: "event-3",
+        },
+      ]);
+    });
+
+    test("should handle empty events array", async () => {
+      await service.handleEvents(mockSelectedCalendar, []);
+
+      expect(mockRepository.upsertMany).toHaveBeenCalledWith([]);
+      expect(mockRepository.deleteMany).toHaveBeenCalledWith([]);
+    });
+
+    test("should handle events with missing optional fields", async () => {
+      const events: CalendarSubscriptionEventItem[] = [
+        {
+          id: "event-1",
+          iCalUID: "event-1@cal.com",
+          start: new Date("2023-12-01T10:00:00Z"),
+          end: new Date("2023-12-01T11:00:00Z"),
+          busy: true,
+          summary: null,
+          description: null,
+          location: null,
+          status: "confirmed",
+          isAllDay: undefined,
+          timeZone: null,
+          recurringEventId: null,
+          originalStartDate: null,
+          createdAt: null,
+          updatedAt: null,
+          etag: null,
+          kind: null,
+        },
+      ];
+
+      await service.handleEvents(mockSelectedCalendar, events);
+
+      expect(mockRepository.upsertMany).toHaveBeenCalledWith([
+        {
+          externalId: "event-1",
+          selectedCalendarId: "test-calendar-id",
+          start: new Date("2023-12-01T10:00:00Z"),
+          end: new Date("2023-12-01T11:00:00Z"),
+          summary: null,
+          description: null,
+          location: null,
+          isAllDay: undefined,
+          timeZone: null,
+          originalStartTime: null,
+          recurringEventId: null,
+          externalEtag: "",
+          externalCreatedAt: null,
+          externalUpdatedAt: null,
+        },
+      ]);
+    });
+  });
+
+  describe("cleanupCache", () => {
+    test("should delete all events for selected calendar", async () => {
+      await service.cleanupCache(mockSelectedCalendar);
+
+      expect(mockRepository.deleteAllBySelectedCalendarId).toHaveBeenCalledWith("test-calendar-id");
+    });
+  });
+
+  describe("cleanupStaleCache", () => {
+    test("should delete stale events", async () => {
+      await service.cleanupStaleCache();
+
+      expect(mockRepository.deleteStale).toHaveBeenCalled();
+    });
+  });
+
+  describe("isCalendarTypeSupported", () => {
+    test("should return true for supported calendar types", () => {
+      expect(CalendarCacheEventService.isCalendarTypeSupported("google_calendar")).toBe(true);
+    });
+
+    test("should return false for unsupported calendar types", () => {
+      expect(CalendarCacheEventService.isCalendarTypeSupported("office365_calendar")).toBe(false);
+      expect(CalendarCacheEventService.isCalendarTypeSupported("outlook_calendar")).toBe(false);
+      expect(CalendarCacheEventService.isCalendarTypeSupported("apple_calendar")).toBe(false);
+      expect(CalendarCacheEventService.isCalendarTypeSupported("unknown_calendar")).toBe(false);
+    });
+
+    test("should return false for null or undefined", () => {
+      expect(CalendarCacheEventService.isCalendarTypeSupported(null)).toBe(false);
+      expect(CalendarCacheEventService.isCalendarTypeSupported(undefined)).toBe(false);
+    });
+  });
+});
@@ -0,0 +1,98 @@
+import type { CalendarSubscriptionEventItem } from "@calcom/features/calendar-subscription/lib/CalendarSubscriptionPort.interface";
+import logger from "@calcom/lib/logger";
+import { BookingRepository } from "@calcom/lib/server/repository/booking";
+import type { SelectedCalendar } from "@calcom/prisma/client";
+
+const log = logger.getSubLogger({ prefix: ["CalendarSyncService"] });
+
+/**
+ * Service to handle synchronization of calendar events.
+ */
+export class CalendarSyncService {
+  constructor(
+    private deps: {
+      bookingRepository: BookingRepository;
+    }
+  ) {}
+
+  /**
+   * Handles synchronization of calendar events
+   *
+   * @param selectedCalendar calendar to process
+   * @param calendarSubscriptionEvents events to process
+   * @returns
+   */
+  async handleEvents(
+    selectedCalendar: SelectedCalendar,
+    calendarSubscriptionEvents: CalendarSubscriptionEventItem[]
+  ) {
+    log.debug("handleEvents", {
+      externalId: selectedCalendar.externalId,
+      countEvents: calendarSubscriptionEvents.length,
+    });
+
+    // only process cal.com calendar events
+    const calEvents = calendarSubscriptionEvents.filter((e) =>
+      e.iCalUID?.toLowerCase()?.endsWith("@cal.com")
+    );
+    if (calEvents.length === 0) {
+      log.debug("handleEvents: no calendar events to process");
+      return;
+    }
+
+    log.debug("handleEvents: processing calendar events", { count: calEvents.length });
+
+    await Promise.all(
+      calEvents.map((e) => {
+        if (e.status === "cancelled") {
+          return this.cancelBooking(e);
+        } else {
+          return this.rescheduleBooking(e);
+        }
+      })
+    );
+  }
+
+  /**
+   * Cancels a booking
+   * @param event
+   * @returns
+   */
+  async cancelBooking(event: CalendarSubscriptionEventItem) {
+    log.debug("cancelBooking", { event });
+    const [bookingUid] = event.iCalUID?.split("@") ?? [undefined];
+    if (!bookingUid) {
+      log.debug("Unable to sync, booking not found");
+      return;
+    }
+
+    const booking = await this.deps.bookingRepository.findBookingByUidWithEventType({ bookingUid });
+    if (!booking) {
+      log.debug("Unable to sync, booking not found");
+      return;
+    }
+
+    // todo handle cancel booking
+  }
+
+  /**
+   * Reschedule a booking
+   * @param event
+   */
+  async rescheduleBooking(event: CalendarSubscriptionEventItem) {
+    log.debug("rescheduleBooking", { event });
+    const [bookingUid] = event.iCalUID?.split("@") ?? [undefined];
+    if (!bookingUid) {
+      log.debug("Unable to sync, booking not found");
+      return;
+    }
+
+    const booking = await this.deps.bookingRepository.findBookingByUidWithEventType({ bookingUid });
+    if (!booking) {
+      log.debug("Unable to sync, booking not found");
+      return;
+    }
+
+    // todo handle update booking
+  }
+}
@@ -26,6 +26,8 @@ export type AppFlags = {
  "team-booking-page-cache": boolean;
  "cal-ai-voice-agents": boolean;
  "tiered-support-chat": boolean;
+  "calendar-subscription-cache": boolean;
+  "calendar-subscription-sync": boolean;
 };

 export type TeamFeatures = Record<keyof AppFlags, boolean>;
@@ -2,6 +2,7 @@ import { captureException } from "@sentry/nextjs";

 import type { PrismaClient } from "@calcom/prisma";
 import { Prisma } from "@calcom/prisma/client";
+
 import type { AppFlags, TeamFeatures } from "./config";
 import type { IFeaturesRepository } from "./features.repository.interface";

@@ -15,6 +16,7 @@ interface CacheOptions {
 * for users, teams, and global application features.
 */
 export class FeaturesRepository implements IFeaturesRepository {
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  private static featuresCache: { data: any[]; expiry: number } | null = null;

  constructor(private prismaClient: PrismaClient) {}
@@ -25,6 +25,8 @@ const initialData: AppFlags = {
  "team-booking-page-cache": false,
  "cal-ai-voice-agents": false,
  "tiered-support-chat": false,
+  "calendar-subscription-cache": false,
+  "calendar-subscription-sync": false,
 };

 if (process.env.NEXT_PUBLIC_IS_E2E) {
@@ -0,0 +1,62 @@
+import type { Prisma, SelectedCalendar } from "@calcom/prisma/client";
+
+export interface ISelectedCalendarRepository {
+  /**
+   * Find selected calendar by id with credentials
+   *
+   * @param id
+   */
+  findByIdWithCredentials(id: string): Promise<SelectedCalendar | null>;
+
+  /**
+   * Find selected calendar by channel id
+   *
+   * @param channelId
+   */
+  findByChannelId(channelId: string): Promise<SelectedCalendar | null>;
+
+  /**
+   *  Find next batch of selected calendars
+   *  Will check if syncSubscribedAt is null or channelExpiration is greater than current date
+   *
+   * @param take the number of calendars to take
+   * @param integrations the list of integrations
+   */
+  findNextSubscriptionBatch({
+    take,
+    integrations,
+  }: {
+    take: number;
+    integrations?: string[];
+  }): Promise<SelectedCalendar[]>;
+
+  /**
+   * Update status of sync for selected calendar
+   *
+   * @param id
+   * @param data
+   */
+  updateSyncStatus(
+    id: string,
+    data: Pick<
+      Prisma.SelectedCalendarUpdateInput,
+      "syncToken" | "syncedAt" | "syncErrorAt" | "syncErrorCount"
+    >
+  ): Promise<SelectedCalendar>;
+
+  /**
+   * Update subscription status for selected calendar
+   */
+  updateSubscription(
+    id: string,
+    data: Pick<
+      Prisma.SelectedCalendarUpdateInput,
+      | "channelId"
+      | "channelResourceId"
+      | "channelResourceUri"
+      | "channelKind"
+      | "channelExpiration"
+      | "syncSubscribedAt"
+    >
+  ): Promise<SelectedCalendar>;
+}
@@ -0,0 +1,83 @@
+import type { ISelectedCalendarRepository } from "@calcom/lib/server/repository/SelectedCalendarRepository.interface";
+import type { PrismaClient } from "@calcom/prisma";
+import type { Prisma } from "@calcom/prisma/client";
+
+export class SelectedCalendarRepository implements ISelectedCalendarRepository {
+  constructor(private prismaClient: PrismaClient) {}
+
+  async findByIdWithCredentials(id: string) {
+    return this.prismaClient.selectedCalendar.findUnique({
+      where: { id },
+      include: {
+        credential: {
+          select: {
+            delegationCredential: true,
+          },
+        },
+      },
+    });
+  }
+
+  async findByChannelId(channelId: string) {
+    return this.prismaClient.selectedCalendar.findFirst({ where: { channelId } });
+  }
+
+  async findNextSubscriptionBatch({ take, integrations }: { take: number; integrations: string[] }) {
+    return this.prismaClient.selectedCalendar.findMany({
+      where: {
+        integration: { in: integrations },
+        OR: [{ syncSubscribedAt: null }, { channelExpiration: { lte: new Date() } }],
+        // initially we will run subscription only for teams that have
+        // the feature flags enabled and it should be removed later
+        user: {
+          teams: {
+            some: {
+              team: {
+                features: {
+                  some: {
+                    OR: [
+                      { featureId: "calendar-subscription-cache" },
+                      { featureId: "calendar-subscription-sync" },
+                    ],
+                  },
+                },
+              },
+            },
+          },
+        },
+      },
+      take,
+    });
+  }
+
+  async updateSyncStatus(
+    id: string,
+    data: Pick<
+      Prisma.SelectedCalendarUpdateInput,
+      "syncToken" | "syncedAt" | "syncErrorAt" | "syncErrorCount"
+    >
+  ) {
+    return this.prismaClient.selectedCalendar.update({
+      where: { id },
+      data,
+    });
+  }
+
+  async updateSubscription(
+    id: string,
+    data: Pick<
+      Prisma.SelectedCalendarUpdateInput,
+      | "channelId"
+      | "channelResourceId"
+      | "channelResourceUri"
+      | "channelKind"
+      | "channelExpiration"
+      | "syncSubscribedAt"
+    >
+  ) {
+    return this.prismaClient.selectedCalendar.update({
+      where: { id },
+      data,
+    });
+  }
+}
@@ -0,0 +1,315 @@
+import { describe, test, expect, vi, beforeEach } from "vitest";
+
+import type { PrismaClient } from "@calcom/prisma";
+import type { Prisma, SelectedCalendar } from "@calcom/prisma/client";
+
+import { SelectedCalendarRepository } from "../SelectedCalendarRepository";
+
+const mockPrismaClient = {
+  selectedCalendar: {
+    findUnique: vi.fn(),
+    findFirst: vi.fn(),
+    findMany: vi.fn(),
+    update: vi.fn(),
+  },
+} as unknown as PrismaClient;
+
+const mockSelectedCalendar: SelectedCalendar = {
+  id: "test-calendar-id",
+  userId: 1,
+  credentialId: 1,
+  integration: "google_calendar",
+  externalId: "test@example.com",
+  eventTypeId: null,
+  delegationCredentialId: null,
+  domainWideDelegationCredentialId: null,
+  googleChannelId: null,
+  googleChannelKind: null,
+  googleChannelResourceId: null,
+  googleChannelResourceUri: null,
+  googleChannelExpiration: null,
+  error: null,
+  lastErrorAt: null,
+  watchAttempts: 0,
+  maxAttempts: 3,
+  unwatchAttempts: 0,
+  createdAt: new Date(),
+  updatedAt: new Date(),
+  channelId: "test-channel-id",
+  channelKind: "web_hook",
+  channelResourceId: "test-resource-id",
+  channelResourceUri: "test-resource-uri",
+  channelExpiration: new Date(Date.now() + 86400000),
+  syncSubscribedAt: new Date(),
+  syncToken: "test-sync-token",
+  syncedAt: new Date(),
+  syncErrorAt: null,
+  syncErrorCount: 0,
+};
+
+describe("SelectedCalendarRepository", () => {
+  let repository: SelectedCalendarRepository;
+
+  beforeEach(() => {
+    repository = new SelectedCalendarRepository(mockPrismaClient);
+    vi.clearAllMocks();
+  });
+
+  describe("findByIdWithCredentials", () => {
+    test("should find selected calendar by id with credential delegation", async () => {
+      const mockCalendarWithCredential = {
+        ...mockSelectedCalendar,
+        credential: {
+          delegationCredential: {
+            id: "delegation-id",
+            key: { client_email: "test@service.com" },
+          },
+        },
+      };
+
+      vi.mocked(mockPrismaClient.selectedCalendar.findUnique).mockResolvedValue(mockCalendarWithCredential);
+
+      const result = await repository.findByIdWithCredentials("test-calendar-id");
+
+      expect(mockPrismaClient.selectedCalendar.findUnique).toHaveBeenCalledWith({
+        where: { id: "test-calendar-id" },
+        include: {
+          credential: {
+            select: {
+              delegationCredential: true,
+            },
+          },
+        },
+      });
+
+      expect(result).toEqual(mockCalendarWithCredential);
+    });
+
+    test("should return null when calendar not found", async () => {
+      vi.mocked(mockPrismaClient.selectedCalendar.findUnique).mockResolvedValue(null);
+
+      const result = await repository.findByIdWithCredentials("non-existent-id");
+
+      expect(result).toBeNull();
+    });
+  });
+
+  describe("findByChannelId", () => {
+    test("should find selected calendar by channel id", async () => {
+      vi.mocked(mockPrismaClient.selectedCalendar.findFirst).mockResolvedValue(mockSelectedCalendar);
+
+      const result = await repository.findByChannelId("test-channel-id");
+
+      expect(mockPrismaClient.selectedCalendar.findFirst).toHaveBeenCalledWith({
+        where: { channelId: "test-channel-id" },
+      });
+
+      expect(result).toEqual(mockSelectedCalendar);
+    });
+
+    test("should return null when calendar not found", async () => {
+      vi.mocked(mockPrismaClient.selectedCalendar.findFirst).mockResolvedValue(null);
+
+      const result = await repository.findByChannelId("non-existent-channel-id");
+
+      expect(result).toBeNull();
+    });
+  });
+
+  describe("findNextSubscriptionBatch", () => {
+    test("should find next batch of calendars for subscription", async () => {
+      const mockCalendars = [mockSelectedCalendar];
+      vi.mocked(mockPrismaClient.selectedCalendar.findMany).mockResolvedValue(mockCalendars);
+
+      const result = await repository.findNextSubscriptionBatch({
+        take: 10,
+        integrations: ["google_calendar", "office365_calendar"],
+      });
+
+      expect(mockPrismaClient.selectedCalendar.findMany).toHaveBeenCalledWith({
+        where: {
+          integration: { in: ["google_calendar", "office365_calendar"] },
+          OR: [{ syncSubscribedAt: null }, { channelExpiration: { lte: expect.any(Date) } }],
+          user: {
+            teams: {
+              some: {
+                team: {
+                  features: {
+                    some: {
+                      OR: [
+                        { featureId: "calendar-subscription-cache" },
+                        { featureId: "calendar-subscription-sync" },
+                      ],
+                    },
+                  },
+                },
+              },
+            },
+          },
+        },
+        take: 10,
+      });
+
+      expect(result).toEqual(mockCalendars);
+    });
+
+    test("should handle empty integrations array", async () => {
+      const mockCalendars = [mockSelectedCalendar];
+      vi.mocked(mockPrismaClient.selectedCalendar.findMany).mockResolvedValue(mockCalendars);
+
+      const result = await repository.findNextSubscriptionBatch({
+        take: 5,
+        integrations: [],
+      });
+
+      expect(mockPrismaClient.selectedCalendar.findMany).toHaveBeenCalledWith({
+        where: {
+          integration: { in: [] },
+          OR: [{ syncSubscribedAt: null }, { channelExpiration: { lte: expect.any(Date) } }],
+          user: {
+            teams: {
+              some: {
+                team: {
+                  features: {
+                    some: {
+                      OR: [
+                        { featureId: "calendar-subscription-cache" },
+                        { featureId: "calendar-subscription-sync" },
+                      ],
+                    },
+                  },
+                },
+              },
+            },
+          },
+        },
+        take: 5,
+      });
+
+      expect(result).toEqual(mockCalendars);
+    });
+  });
+
+  describe("updateSyncStatus", () => {
+    test("should update sync status", async () => {
+      const updateData: Pick<
+        Prisma.SelectedCalendarUpdateInput,
+        "syncToken" | "syncedAt" | "syncErrorAt" | "syncErrorCount"
+      > = {
+        syncToken: "new-sync-token",
+        syncedAt: new Date(),
+        syncErrorAt: null,
+        syncErrorCount: 0,
+      };
+
+      const updatedCalendar = {
+        ...mockSelectedCalendar,
+        ...updateData,
+      };
+
+      vi.mocked(mockPrismaClient.selectedCalendar.update).mockResolvedValue(updatedCalendar);
+
+      const result = await repository.updateSyncStatus("test-calendar-id", updateData);
+
+      expect(mockPrismaClient.selectedCalendar.update).toHaveBeenCalledWith({
+        where: { id: "test-calendar-id" },
+        data: updateData,
+      });
+
+      expect(result).toEqual(updatedCalendar);
+    });
+
+    test("should update sync error status", async () => {
+      const updateData: Pick<
+        Prisma.SelectedCalendarUpdateInput,
+        "syncToken" | "syncedAt" | "syncErrorAt" | "syncErrorCount"
+      > = {
+        syncErrorAt: new Date(),
+        syncErrorCount: 1,
+      };
+
+      const updatedCalendar = {
+        ...mockSelectedCalendar,
+        ...updateData,
+      };
+
+      vi.mocked(mockPrismaClient.selectedCalendar.update).mockResolvedValue(updatedCalendar);
+
+      const result = await repository.updateSyncStatus("test-calendar-id", updateData);
+
+      expect(mockPrismaClient.selectedCalendar.update).toHaveBeenCalledWith({
+        where: { id: "test-calendar-id" },
+        data: updateData,
+      });
+
+      expect(result).toEqual(updatedCalendar);
+    });
+  });
+
+  describe("updateSubscription", () => {
+    test("should update subscription status", async () => {
+      const updateData: Pick<
+        Prisma.SelectedCalendarUpdateInput,
+        | "channelId"
+        | "channelResourceId"
+        | "channelResourceUri"
+        | "channelKind"
+        | "channelExpiration"
+        | "syncSubscribedAt"
+      > = {
+        channelId: "new-channel-id",
+        channelResourceId: "new-resource-id",
+        channelResourceUri: "new-resource-uri",
+        channelKind: "web_hook",
+        channelExpiration: new Date(Date.now() + 86400000),
+        syncSubscribedAt: new Date(),
+      };
+
+      const updatedCalendar = {
+        ...mockSelectedCalendar,
+        ...updateData,
+      };
+
+      vi.mocked(mockPrismaClient.selectedCalendar.update).mockResolvedValue(updatedCalendar);
+
+      const result = await repository.updateSubscription("test-calendar-id", updateData);
+
+      expect(mockPrismaClient.selectedCalendar.update).toHaveBeenCalledWith({
+        where: { id: "test-calendar-id" },
+        data: updateData,
+      });
+
+      expect(result).toEqual(updatedCalendar);
+    });
+
+    test("should unsubscribe by setting syncSubscribedAt to null", async () => {
+      const updateData: Pick<
+        Prisma.SelectedCalendarUpdateInput,
+        | "channelId"
+        | "channelResourceId"
+        | "channelResourceUri"
+        | "channelKind"
+        | "channelExpiration"
+        | "syncSubscribedAt"
+      > = {
+        syncSubscribedAt: null,
+      };
+
+      const updatedCalendar = {
+        ...mockSelectedCalendar,
+        syncSubscribedAt: null,
+      };
+
+      vi.mocked(mockPrismaClient.selectedCalendar.update).mockResolvedValue(updatedCalendar);
+
+      const result = await repository.updateSubscription("test-calendar-id", updateData);
+
+      expect(mockPrismaClient.selectedCalendar.update).toHaveBeenCalledWith({
+        where: { id: "test-calendar-id" },
+        data: updateData,
+      });
+
+      expect(result).toEqual(updatedCalendar);
+    });
+  });
+});
@@ -387,6 +387,17 @@ export class BookingRepository {
    });
  }

+  async findBookingByUidWithEventType({ bookingUid }: { bookingUid: string }) {
+    return await this.prismaClient.booking.findUnique({
+      where: {
+        uid: bookingUid,
+      },
+      include: {
+        eventType: true,
+      },
+    });
+  }
+
  async findByIdIncludeUserAndAttendees(bookingId: number) {
    return await this.prismaClient.booking.findUnique({
      where: {
@@ -725,13 +736,9 @@ export class BookingRepository {
            },
          },
        },
-        // eslint-disable-next-line @calcom/eslint/no-prisma-include-true
        destinationCalendar: true,
-        // eslint-disable-next-line @calcom/eslint/no-prisma-include-true
        payment: true,
-        // eslint-disable-next-line @calcom/eslint/no-prisma-include-true
        references: true,
-        // eslint-disable-next-line @calcom/eslint/no-prisma-include-true
        workflowReminders: true,
      },
    });
@@ -873,13 +880,9 @@ export class BookingRepository {
        status: filterForUnconfirmed ? BookingStatus.PENDING : BookingStatus.ACCEPTED,
      },
      include: {
-        // eslint-disable-next-line @calcom/eslint/no-prisma-include-true
        attendees: true,
-        // eslint-disable-next-line @calcom/eslint/no-prisma-include-true
        references: true,
-        // eslint-disable-next-line @calcom/eslint/no-prisma-include-true
        user: true,
-        // eslint-disable-next-line @calcom/eslint/no-prisma-include-true
        payment: true,
      },
    });
@@ -0,0 +1,58 @@
+/*
+  Warnings:
+
+  - Added calendar cache and sync fields to SelectedCalendar table
+  - Created CalendarCacheEvent table with CalendarCacheEventStatus enum
+
+*/
+
+CREATE TYPE "CalendarCacheEventStatus" AS ENUM ('confirmed', 'tentative', 'cancelled');
+
+-- AlterTable
+ALTER TABLE "SelectedCalendar" ADD COLUMN     "channelId" TEXT,
+ADD COLUMN     "channelKind" TEXT,
+ADD COLUMN     "channelResourceId" TEXT,
+ADD COLUMN     "channelResourceUri" TEXT,
+ADD COLUMN     "channelExpiration" TIMESTAMP(3),
+ADD COLUMN     "syncSubscribedAt" TIMESTAMP(3),
+ADD COLUMN     "syncToken" TEXT,
+ADD COLUMN     "syncedAt" TIMESTAMP(3),
+ADD COLUMN     "syncErrorAt" TIMESTAMP(3),
+ADD COLUMN     "syncErrorCount" INTEGER DEFAULT 0;
+
+CREATE TABLE "CalendarCacheEvent" (
+    "id" TEXT NOT NULL,
+    "selectedCalendarId" TEXT NOT NULL,
+    "externalId" TEXT NOT NULL,
+    "externalEtag" TEXT NOT NULL,
+    "iCalUID" TEXT,
+    "iCalSequence" INTEGER NOT NULL DEFAULT 0,
+    "summary" TEXT,
+    "description" TEXT,
+    "location" TEXT,
+    "start" TIMESTAMP(3) NOT NULL,
+    "end" TIMESTAMP(3) NOT NULL,
+    "isAllDay" BOOLEAN NOT NULL DEFAULT false,
+    "timeZone" TEXT,
+    "status" "CalendarCacheEventStatus" NOT NULL DEFAULT 'confirmed',
+    "recurringEventId" TEXT,
+    "originalStartTime" TIMESTAMP(3),
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+    "externalCreatedAt" TIMESTAMP(3),
+    "externalUpdatedAt" TIMESTAMP(3),
+
+    CONSTRAINT "CalendarCacheEvent_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE UNIQUE INDEX "CalendarCacheEvent_selectedCalendarId_externalId_key" ON "CalendarCacheEvent"("selectedCalendarId", "externalId");
+
+-- CreateIndex
+CREATE INDEX "CalendarCacheEvent_start_end_status_idx" ON "CalendarCacheEvent"("start", "end", "status");
+
+-- CreateIndex
+CREATE INDEX "CalendarCacheEvent_selectedCalendarId_iCalUID_idx" ON "CalendarCacheEvent"("selectedCalendarId", "iCalUID");
+
+-- AddForeignKey
+ALTER TABLE "CalendarCacheEvent" ADD CONSTRAINT "CalendarCacheEvent_selectedCalendarId_fkey" FOREIGN KEY ("selectedCalendarId") REFERENCES "SelectedCalendar"("id") ON DELETE CASCADE ON UPDATE CASCADE;
@@ -0,0 +1,8 @@
+-- FeatureFlags
+INSERT INTO "Feature" (slug, enabled, description, "type")
+VALUES ('calendar-subscription-sync', false, 'Enable calendar subscription synchronization', 'OPERATIONAL')
+ON CONFLICT (slug) DO NOTHING;
+
+INSERT INTO "Feature" (slug, enabled, description, "type")
+VALUES ('calendar-subscription-cache', false, 'Enable calendar subscription cache', 'OPERATIONAL')
+ON CONFLICT (slug) DO NOTHING;
@@ -904,21 +904,44 @@ model Availability {
 }

 model SelectedCalendar {
-  id                       String      @id @default(uuid())
-  user                     User        @relation(fields: [userId], references: [id], onDelete: Cascade)
-  userId                   Int
-  integration              String
-  externalId               String
-  credential               Credential? @relation(fields: [credentialId], references: [id], onDelete: Cascade)
-  credentialId             Int?
-  createdAt                DateTime?   @default(now())
-  updatedAt                DateTime?   @updatedAt
+  id              String      @id @default(uuid())
+  user            User        @relation(fields: [userId], references: [id], onDelete: Cascade)
+  userId          Int
+  integration     String
+  externalId      String
+  credential      Credential? @relation(fields: [credentialId], references: [id], onDelete: Cascade)
+  credentialId    Int?
+  createdAt       DateTime?   @default(now())
+  updatedAt       DateTime?   @updatedAt
  // Used to identify a watched calendar channel in Google Calendar
-  googleChannelId          String?
-  googleChannelKind        String?
-  googleChannelResourceId  String?
+  // @deprecated use channelId instead
+  googleChannelId String?
+
+  // @deprecated use channelKind instead
+  googleChannelKind String?
+
+  // @deprecated use channelResourceId instead
+  googleChannelResourceId String?
+
+  // @deprecated use channelResourceUri instead
  googleChannelResourceUri String?
-  googleChannelExpiration  String?
+
+  // @deprecated use channelExpoiration instead
+  googleChannelExpiration String?
+
+  // Used to identify a watched calendar
+  channelId          String?
+  channelKind        String?
+  channelResourceId  String?
+  channelResourceUri String?
+  channelExpiration  DateTime? @db.Timestamp(3)
+
+  // Used to calendar cache and sync
+  syncSubscribedAt DateTime? @db.Timestamp(3)
+  syncToken        String?
+  syncedAt         DateTime?
+  syncErrorAt      DateTime?
+  syncErrorCount   Int?      @default(0)

  delegationCredential   DelegationCredential? @relation(fields: [delegationCredentialId], references: [id], onDelete: Cascade)
  delegationCredentialId String?
@@ -935,6 +958,8 @@ model SelectedCalendar {
  eventTypeId Int?
  eventType   EventType? @relation(fields: [eventTypeId], references: [id])

+  calendarCacheEvents CalendarCacheEvent[]
+
  // It could still allow multiple user-level(eventTypeId is null) selected calendars for same userId, integration, externalId because NULL is not equal to NULL
  // We currently ensure uniqueness by checking for the existence of the record before creating a new one
  // Think about introducing a generated unique key ${userId}_${integration}_${externalId}_${eventTypeId}
@@ -2571,3 +2596,41 @@ model CalAiPhoneNumber {
  @@index([inboundAgentId])
  @@index([outboundAgentId])
 }
+
+enum CalendarCacheEventStatus {
+  confirmed @map("confirmed")
+  tentative @map("tentative")
+  cancelled @map("cancelled")
+}
+
+model CalendarCacheEvent {
+  id                 String  @id @default(uuid())
+  selectedCalendarId String
+  externalId         String
+  externalEtag       String
+  iCalUID            String?
+  iCalSequence       Int     @default(0)
+
+  // Event details
+  summary           String?
+  description       String?
+  location          String?
+  start             DateTime
+  end               DateTime
+  isAllDay          Boolean                  @default(false)
+  timeZone          String?
+  status            CalendarCacheEventStatus @default(confirmed)
+  recurringEventId  String?
+  originalStartTime DateTime?
+
+  createdAt         DateTime  @default(now())
+  updatedAt         DateTime  @updatedAt
+  externalCreatedAt DateTime?
+  externalUpdatedAt DateTime?
+
+  selectedCalendar SelectedCalendar @relation(fields: [selectedCalendarId], references: [id], onDelete: Cascade)
+
+  @@unique([selectedCalendarId, externalId])
+  @@index([start, end, status])
+  @@index([selectedCalendarId, iCalUID])
+}
@@ -81,6 +81,7 @@
    "GOOGLE_API_CREDENTIALS",
    "GOOGLE_LOGIN_ENABLED",
    "GOOGLE_WEBHOOK_TOKEN",
+    "GOOGLE_WEBHOOK_URL",
    "HEROKU_APP_NAME",
    "HUBSPOT_CLIENT_ID",
    "HUBSPOT_CLIENT_SECRET",
@@ -280,6 +281,8 @@
    "ATOMS_E2E_APPLE_CONNECT_APP_SPECIFIC_PASSCODE",
    "INTERCOM_API_TOKEN",
    "NEXT_PUBLIC_INTERCOM_APP_ID",
+    "MICROSOFT_WEBHOOK_TOKEN",
+    "MICROSOFT_WEBHOOK_URL",
    "_CAL_INTERNAL_PAST_BOOKING_RESCHEDULE_CHANGE_TEAM_IDS",
    "ENTERPRISE_SLUGS",
    "PLATFORM_ENTERPRISE_SLUGS"