diff --git a/apps/api/src/controllers/Webhooks.ts b/apps/api/src/controllers/Webhooks.ts
index 87f61d4..628362f 100644
--- a/apps/api/src/controllers/Webhooks.ts
+++ b/apps/api/src/controllers/Webhooks.ts
@@ -8,6 +8,7 @@ import type Stripe from 'stripe';
 import {STRIPE_ENABLED, STRIPE_WEBHOOK_SECRET} from '../app/constants.js';
 import {stripe} from '../app/stripe.js';
 import {prisma} from '../database/prisma.js';
+import {EventService} from '../services/EventService.js';
 import {SecurityService} from '../services/SecurityService.js';
 import {CatchAsync} from '../utils/asyncHandler.js';
 
@@ -23,7 +24,7 @@ export class Webhooks {
    */
   @Post('sns')
   @CatchAsync
-  public async receiveSNSWebhook(req: Request, res: Response, next: NextFunction) {
+  public async receiveSNSWebhook(req: Request, res: Response) {
     try {
       // Handle SNS subscription confirmation FIRST (before parsing Message field)
       if (req.body.Type === 'SubscriptionConfirmation') {
@@ -90,7 +91,18 @@ export class Webhooks {
       const now = new Date();
       const updateData: Prisma.EmailUpdateInput = {};
       const eventName = `email.${eventType.toLowerCase()}`;
-      let eventData: Record<string, unknown> = {};
+
+      // Base event data with email metadata
+      const baseEventData = {
+        subject: email.subject,
+        from: email.from,
+        fromName: email.fromName,
+        messageId: email.messageId,
+        templateId: email.templateId,
+        campaignId: email.campaignId,
+        sourceType: email.sourceType,
+      };
+      let eventData: Record<string, unknown> = baseEventData;
 
       // Process event based on type
       switch (eventType) {
@@ -98,6 +110,10 @@ export class Webhooks {
           signale.success(`[WEBHOOK] Delivery confirmed for ${email.contact.email} from ${email.project.name}`);
           updateData.status = EmailStatus.DELIVERED;
           updateData.deliveredAt = now;
+          eventData = {
+            ...baseEventData,
+            deliveredAt: now.toISOString(),
+          };
           break;
 
         case 'Open':
@@ -108,6 +124,12 @@ export class Webhooks {
           }
           updateData.opens = (email.opens || 0) + 1;
           updateData.status = EmailStatus.OPENED;
+          eventData = {
+            ...baseEventData,
+            openedAt: email.openedAt?.toISOString() || now.toISOString(),
+            opens: (email.opens || 0) + 1,
+            isFirstOpen: !email.openedAt,
+          };
           break;
 
         case 'Click': {
@@ -119,7 +141,13 @@ export class Webhooks {
           }
           updateData.clicks = (email.clicks || 0) + 1;
           updateData.status = EmailStatus.CLICKED;
-          eventData = {link: clickedLink};
+          eventData = {
+            ...baseEventData,
+            link: clickedLink,
+            clickedAt: email.clickedAt?.toISOString() || now.toISOString(),
+            clicks: (email.clicks || 0) + 1,
+            isFirstClick: !email.clickedAt,
+          };
           break;
         }
 
@@ -132,7 +160,11 @@ export class Webhooks {
             where: {id: email.contactId},
             data: {subscribed: false},
           });
-          eventData = body.bounce ? {bounceType: body.bounce.bounceType} : {};
+          eventData = {
+            ...baseEventData,
+            bounceType: body.bounce?.bounceType,
+            bouncedAt: now.toISOString(),
+          };
           break;
 
         case 'Complaint':
@@ -144,6 +176,10 @@ export class Webhooks {
             where: {id: email.contactId},
             data: {subscribed: false},
           });
+          eventData = {
+            ...baseEventData,
+            complainedAt: now.toISOString(),
+          };
           break;
 
         default:
@@ -157,16 +193,8 @@ export class Webhooks {
         data: updateData,
       });
 
-      // Track event
-      await prisma.event.create({
-        data: {
-          projectId: email.projectId,
-          contactId: email.contactId,
-          emailId: email.id,
-          name: eventName,
-          data: eventData as Prisma.InputJsonValue,
-        },
-      });
+      // Track event (this will trigger workflows)
+      await EventService.trackEvent(email.projectId, eventName, email.contactId, email.id, eventData);
 
       // Check security limits for bounce and complaint events
       if (eventType === 'Bounce' || eventType === 'Complaint') {
@@ -188,7 +216,7 @@ export class Webhooks {
    */
   @Post('incoming/stripe')
   @CatchAsync
-  public async receiveStripeWebhook(req: Request, res: Response, next: NextFunction) {
+  public async receiveStripeWebhook(req: Request, res: Response) {
     // Return 404 if billing is disabled
     if (!STRIPE_ENABLED || !stripe) {
       signale.warn('[WEBHOOK] Stripe webhook received but billing is disabled');
diff --git a/apps/api/src/controllers/Workflows.ts b/apps/api/src/controllers/Workflows.ts
index 810f2ea..74a1de1 100644
--- a/apps/api/src/controllers/Workflows.ts
+++ b/apps/api/src/controllers/Workflows.ts
@@ -4,6 +4,8 @@ import type {NextFunction, Request, Response} from 'express';
 
 import type {AuthResponse} from '../middleware/auth.js';
 import {requireAuth} from '../middleware/auth.js';
+import {ContactService} from '../services/ContactService.js';
+import {EventService} from '../services/EventService.js';
 import {WorkflowService} from '../services/WorkflowService.js';
 import {CatchAsync} from '../utils/asyncHandler.js';
 
@@ -27,6 +29,45 @@ export class Workflows {
     return res.status(200).json(result);
   }
 
+  /**
+   * GET /workflows/fields
+   * Get all available fields for workflow conditions (contact fields + event fields)
+   * Query param: eventName - Optional event name to filter event fields
+   * NOTE: This must be defined BEFORE the :id route to avoid conflicts
+   */
+  @Get('fields')
+  @Middleware([requireAuth])
+  @CatchAsync
+  public async getAvailableFields(req: Request, res: Response, next: NextFunction) {
+    const auth = res.locals.auth as AuthResponse;
+    const eventName = req.query.eventName as string | undefined;
+
+    try {
+      // Get contact fields (standard + custom data fields)
+      const contactFields = await ContactService.getAvailableFields(auth.projectId!);
+
+      // Add standard contact fields
+      const standardContactFields = ['contact.email', 'contact.subscribed'];
+
+      // Get event fields by analyzing actual event data
+      // This will only show fields that have been seen in actual events
+      const eventFields = await EventService.getAvailableEventFields(auth.projectId!, eventName);
+
+      // Combine all fields
+      const allFields = [...standardContactFields, ...contactFields, ...eventFields].sort();
+
+      return res.status(200).json({
+        fields: allFields,
+        count: allFields.length,
+      });
+    } catch (error) {
+      console.error('[WORKFLOWS] Failed to get available fields:', error);
+      return res.status(500).json({
+        error: error instanceof Error ? error.message : 'Failed to get available fields',
+      });
+    }
+  }
+
   /**
    * GET /workflows/:id
    * Get a specific workflow with all steps and transitions
diff --git a/apps/api/src/controllers/__tests__/Workflows.test.ts b/apps/api/src/controllers/__tests__/Workflows.test.ts
new file mode 100644
index 0000000..e236d31
--- /dev/null
+++ b/apps/api/src/controllers/__tests__/Workflows.test.ts
@@ -0,0 +1,269 @@
+import {describe, it, expect, beforeEach} from 'vitest';
+import {WorkflowTriggerType} from '@plunk/db';
+import request from 'supertest';
+import jwt from 'jsonwebtoken';
+import {app} from '../../app';
+import {JWT_SECRET} from '../../app/constants';
+import {factories, getPrismaClient} from '../../../../../test/helpers';
+import {EventService} from '../../services/EventService';
+
+describe('Workflows Controller', () => {
+  let projectId: string;
+  let userId: string;
+  let authToken: string;
+  const prisma = getPrismaClient();
+
+  beforeEach(async () => {
+    const {project, user} = await factories.createUserWithProject();
+    projectId = project.id;
+    userId = user.id;
+    authToken = jwt.sign({userId: user.id, projectId: project.id}, JWT_SECRET);
+  });
+
+  // ========================================
+  // GET /workflows/fields
+  // ========================================
+  describe('GET /workflows/fields', () => {
+    it('should return contact and event fields', async () => {
+      const contact = await factories.createContact({
+        projectId,
+        data: {
+          firstName: 'John',
+          lastName: 'Doe',
+          plan: 'premium',
+        },
+      });
+
+      // Create email events with data
+      await EventService.trackEvent(projectId, 'email.opened', contact.id, undefined, {
+        subject: 'Welcome',
+        from: 'hello@example.com',
+        openedAt: new Date().toISOString(),
+        isFirstOpen: true,
+      });
+
+      const response = await request(app)
+        .get('/workflows/fields')
+        .set('Authorization', `Bearer ${authToken}`)
+        .expect(200);
+
+      expect(response.body.fields).toBeInstanceOf(Array);
+      expect(response.body.count).toBeGreaterThan(0);
+
+      // Should include standard contact fields
+      expect(response.body.fields).toContain('contact.email');
+      expect(response.body.fields).toContain('contact.subscribed');
+
+      // Should include custom contact data fields
+      expect(response.body.fields).toContain('data.firstName');
+      expect(response.body.fields).toContain('data.lastName');
+      expect(response.body.fields).toContain('data.plan');
+
+      // Should include event fields
+      expect(response.body.fields).toContain('event.subject');
+      expect(response.body.fields).toContain('event.from');
+      expect(response.body.fields).toContain('event.openedAt');
+      expect(response.body.fields).toContain('event.isFirstOpen');
+    });
+
+    it('should filter event fields by eventName query param', async () => {
+      const contact = await factories.createContact({projectId});
+
+      // Create email.opened events
+      await EventService.trackEvent(projectId, 'email.opened', contact.id, undefined, {
+        subject: 'Test',
+        openedAt: new Date().toISOString(),
+        isFirstOpen: true,
+      });
+
+      // Create email.clicked events
+      await EventService.trackEvent(projectId, 'email.clicked', contact.id, undefined, {
+        subject: 'Test',
+        link: 'https://example.com',
+        clickedAt: new Date().toISOString(),
+      });
+
+      // Request fields for email.opened only
+      const response = await request(app)
+        .get('/workflows/fields')
+        .query({eventName: 'email.opened'})
+        .set('Authorization', `Bearer ${authToken}`)
+        .expect(200);
+
+      // Should include email.opened fields
+      expect(response.body.fields).toContain('event.subject');
+      expect(response.body.fields).toContain('event.openedAt');
+      expect(response.body.fields).toContain('event.isFirstOpen');
+
+      // Should NOT include email.clicked fields
+      expect(response.body.fields).not.toContain('event.link');
+      expect(response.body.fields).not.toContain('event.clickedAt');
+    });
+
+    it('should return fields in sorted order', async () => {
+      const contact = await factories.createContact({
+        projectId,
+        data: {
+          zebra: 'last',
+          apple: 'first',
+        },
+      });
+
+      await EventService.trackEvent(projectId, 'test.event', contact.id, undefined, {
+        zoo: 'value',
+        aardvark: 'value',
+      });
+
+      const response = await request(app)
+        .get('/workflows/fields')
+        .set('Authorization', `Bearer ${authToken}`)
+        .expect(200);
+
+      const fields = response.body.fields as string[];
+
+      // Verify fields are sorted
+      const sortedFields = [...fields].sort();
+      expect(fields).toEqual(sortedFields);
+    });
+
+    it('should return empty event fields when no events exist', async () => {
+      const response = await request(app)
+        .get('/workflows/fields')
+        .set('Authorization', `Bearer ${authToken}`)
+        .expect(200);
+
+      // Should still have contact fields
+      expect(response.body.fields).toContain('contact.email');
+      expect(response.body.fields).toContain('contact.subscribed');
+
+      // But no event fields
+      const eventFields = response.body.fields.filter((f: string) => f.startsWith('event.'));
+      expect(eventFields).toHaveLength(0);
+    });
+
+    it('should require authentication', async () => {
+      await request(app).get('/workflows/fields').expect(401);
+    });
+
+    it('should only return fields for authenticated project', async () => {
+      // Create another project with events
+      const {project: otherProject} = await factories.createUserWithProject();
+      const otherContact = await factories.createContact({projectId: otherProject.id});
+
+      await EventService.trackEvent(otherProject.id, 'other.event', otherContact.id, undefined, {
+        secretField: 'secret value',
+      });
+
+      // Request fields with our auth token (different project)
+      const response = await request(app)
+        .get('/workflows/fields')
+        .set('Authorization', `Bearer ${authToken}`)
+        .expect(200);
+
+      // Should not include fields from other project
+      expect(response.body.fields).not.toContain('event.secretField');
+    });
+
+    it('should handle URL encoded event names', async () => {
+      const contact = await factories.createContact({projectId});
+
+      await EventService.trackEvent(projectId, 'email.opened', contact.id, undefined, {
+        field1: 'value',
+      });
+
+      const response = await request(app)
+        .get('/workflows/fields')
+        .query({eventName: 'email.opened'})
+        .set('Authorization', `Bearer ${authToken}`)
+        .expect(200);
+
+      expect(response.body.fields).toContain('event.field1');
+    });
+  });
+
+  // ========================================
+  // Integration Tests
+  // ========================================
+  describe('Workflow field discovery integration', () => {
+    it('should discover correct fields for email.sent events', async () => {
+      const contact = await factories.createContact({projectId});
+      const email = await factories.createEmail(projectId, contact.id);
+
+      // Create email.sent event with actual structure
+      await EventService.trackEvent(projectId, 'email.sent', contact.id, email.id, {
+        subject: 'Welcome Email',
+        from: 'hello@example.com',
+        fromName: 'Example Team',
+        messageId: 'msg-123',
+        templateId: 'tpl-456',
+        campaignId: null,
+        sourceType: 'TRANSACTIONAL',
+        sentAt: new Date().toISOString(),
+      });
+
+      const response = await request(app)
+        .get('/workflows/fields')
+        .query({eventName: 'email.sent'})
+        .set('Authorization', `Bearer ${authToken}`)
+        .expect(200);
+
+      expect(response.body.fields).toContain('event.subject');
+      expect(response.body.fields).toContain('event.from');
+      expect(response.body.fields).toContain('event.fromName');
+      expect(response.body.fields).toContain('event.messageId');
+      expect(response.body.fields).toContain('event.templateId');
+      expect(response.body.fields).toContain('event.sourceType');
+      expect(response.body.fields).toContain('event.sentAt');
+    });
+
+    it('should discover correct fields for email.opened events', async () => {
+      const contact = await factories.createContact({projectId});
+      const email = await factories.createEmail(projectId, contact.id);
+
+      await EventService.trackEvent(projectId, 'email.opened', contact.id, email.id, {
+        subject: 'Newsletter',
+        from: 'news@example.com',
+        fromName: 'Newsletter Team',
+        messageId: 'msg-456',
+        openedAt: new Date().toISOString(),
+        opens: 1,
+        isFirstOpen: true,
+      });
+
+      const response = await request(app)
+        .get('/workflows/fields')
+        .query({eventName: 'email.opened'})
+        .set('Authorization', `Bearer ${authToken}`)
+        .expect(200);
+
+      expect(response.body.fields).toContain('event.openedAt');
+      expect(response.body.fields).toContain('event.opens');
+      expect(response.body.fields).toContain('event.isFirstOpen');
+    });
+
+    it('should discover correct fields for email.clicked events', async () => {
+      const contact = await factories.createContact({projectId});
+      const email = await factories.createEmail(projectId, contact.id);
+
+      await EventService.trackEvent(projectId, 'email.clicked', contact.id, email.id, {
+        subject: 'Sale Announcement',
+        from: 'sales@example.com',
+        link: 'https://example.com/sale',
+        clickedAt: new Date().toISOString(),
+        clicks: 1,
+        isFirstClick: true,
+      });
+
+      const response = await request(app)
+        .get('/workflows/fields')
+        .query({eventName: 'email.clicked'})
+        .set('Authorization', `Bearer ${authToken}`)
+        .expect(200);
+
+      expect(response.body.fields).toContain('event.link');
+      expect(response.body.fields).toContain('event.clickedAt');
+      expect(response.body.fields).toContain('event.clicks');
+      expect(response.body.fields).toContain('event.isFirstClick');
+    });
+  });
+});
diff --git a/apps/api/src/jobs/email-processor.ts b/apps/api/src/jobs/email-processor.ts
index 6dfccea..19f84c5 100644
--- a/apps/api/src/jobs/email-processor.ts
+++ b/apps/api/src/jobs/email-processor.ts
@@ -9,6 +9,7 @@ import {type Job, Worker} from 'bullmq';
 
 import {prisma} from '../database/prisma.js';
 import {EmailService} from '../services/EmailService.js';
+import {EventService} from '../services/EventService.js';
 import {MeterService} from '../services/MeterService.js';
 import {emailQueue, type SendEmailJobData} from '../services/QueueService.js';
 import {sendRawEmail} from '../services/SESService.js';
@@ -119,19 +120,16 @@ export function createEmailWorker() {
           await MeterService.recordEmailSent(email.project.customer, emailCount, `email_${emailId}`);
         }
 
-        // Track event
-        await prisma.event.create({
-          data: {
-            projectId: email.projectId,
-            contactId: email.contactId,
-            emailId: email.id,
-            name: 'email.sent',
-            data: {
-              subject: formattedEmail.subject,
-              from: email.from,
-              messageId: result.messageId,
-            } as Prisma.InputJsonValue,
-          },
+        // Track event (this will trigger workflows)
+        await EventService.trackEvent(email.projectId, 'email.sent', email.contactId, email.id, {
+          subject: formattedEmail.subject,
+          from: email.from,
+          fromName: email.fromName,
+          messageId: result.messageId,
+          templateId: email.templateId,
+          campaignId: email.campaignId,
+          sourceType: email.sourceType,
+          sentAt: new Date().toISOString(),
         });
       } catch (error) {
         console.error(`[EMAIL-PROCESSOR] Failed to send email ${emailId}:`, error);
diff --git a/apps/api/src/services/EmailService.ts b/apps/api/src/services/EmailService.ts
index 3253503..572bd96 100644
--- a/apps/api/src/services/EmailService.ts
+++ b/apps/api/src/services/EmailService.ts
@@ -8,6 +8,7 @@ import {HttpException} from '../exceptions/index.js';
 
 import {BillingLimitService} from './BillingLimitService.js';
 import {DomainService} from './DomainService.js';
+import {EventService} from './EventService.js';
 import {QueueService} from './QueueService.js';
 import {sendRawEmail} from './SESService.js';
 
@@ -386,19 +387,16 @@ export class EmailService {
         },
       });
 
-      // Track event
-      await prisma.event.create({
-        data: {
-          projectId: email.projectId,
-          contactId: email.contactId,
-          emailId: email.id,
-          name: 'email.sent',
-          data: {
-            subject: formattedEmail.subject,
-            from: email.from,
-            messageId: result.messageId,
-          },
-        },
+      // Track event (this will trigger workflows)
+      await EventService.trackEvent(email.projectId, 'email.sent', email.contactId, email.id, {
+        subject: formattedEmail.subject,
+        from: email.from,
+        fromName: email.fromName,
+        messageId: result.messageId,
+        templateId: email.templateId,
+        campaignId: email.campaignId,
+        sourceType: email.sourceType,
+        sentAt: new Date().toISOString(),
       });
     } catch (error) {
       console.error(`[EMAIL] Failed to send email ${emailId}:`, error);
diff --git a/apps/api/src/services/EventService.ts b/apps/api/src/services/EventService.ts
index 3b77e6a..d1c2203 100644
--- a/apps/api/src/services/EventService.ts
+++ b/apps/api/src/services/EventService.ts
@@ -1,4 +1,5 @@
-import type {Event, Prisma} from '@plunk/db';
+import type {Event} from '@plunk/db';
+import {Prisma} from '@plunk/db';
 
 import {prisma} from '../database/prisma.js';
 import {redis} from '../database/redis.js';
@@ -139,6 +140,43 @@ export class EventService {
     return events.map(e => e.name);
   }
 
+  /**
+   * Get available event data fields for a specific event name
+   * Analyzes actual event data to discover which fields are present
+   * This is optimized for large datasets - only samples recent events
+   */
+  public static async getAvailableEventFields(projectId: string, eventName?: string): Promise<string[]> {
+    // Query recent events to discover data fields (limit to 100 for performance)
+    const events = await prisma.event.findMany({
+      where: {
+        projectId,
+        ...(eventName ? {name: eventName} : {}),
+        data: {
+          not: Prisma.DbNull, // Only events with data (not null)
+        },
+      },
+      select: {
+        data: true,
+      },
+      orderBy: {createdAt: 'desc'},
+      take: 100, // Sample recent events for performance
+    });
+
+    // Extract all unique keys from event data
+    const fieldSet = new Set<string>();
+
+    for (const event of events) {
+      if (event.data && typeof event.data === 'object' && !Array.isArray(event.data)) {
+        const data = event.data as Record<string, unknown>;
+        for (const key of Object.keys(data)) {
+          fieldSet.add(`event.${key}`);
+        }
+      }
+    }
+
+    return Array.from(fieldSet).sort();
+  }
+
   /**
    * Trigger workflows based on an event
    * Uses Redis caching for enabled workflows to improve performance
diff --git a/apps/api/src/services/WorkflowExecutionService.ts b/apps/api/src/services/WorkflowExecutionService.ts
index e46d189..a28c041 100644
--- a/apps/api/src/services/WorkflowExecutionService.ts
+++ b/apps/api/src/services/WorkflowExecutionService.ts
@@ -591,7 +591,8 @@ export class WorkflowExecutionService {
     // Structure allows access to:
     // - contact.email, contact.subscribed
     // - data.firstName, data.lastName, etc.
-    // - workflow.* (execution context)
+    // - workflow.* (execution context - alias for event data)
+    // - event.* (event data that triggered the workflow)
     const actualValue = this.resolveField(field, {
       contact: {
         email: contact.email,
@@ -599,6 +600,7 @@ export class WorkflowExecutionService {
       },
       data: contactData,
       workflow: context,
+      event: context, // Alias for easier access to event data
     });
 
     // Evaluate the condition
@@ -665,6 +667,7 @@ export class WorkflowExecutionService {
       contact.data && typeof contact.data === 'object' && !Array.isArray(contact.data)
         ? (contact.data as Record<string, unknown>)
         : {};
+    const context = execution.context || {};
 
     const payload = body || {
       contact: {
@@ -680,6 +683,7 @@ export class WorkflowExecutionService {
         id: execution.id,
         startedAt: execution.startedAt,
       },
+      event: context, // Include event data that triggered the workflow
     };
 
     // Make HTTP request
diff --git a/apps/api/src/services/__tests__/EventService.test.ts b/apps/api/src/services/__tests__/EventService.test.ts
index b90d835..af1b60b 100644
--- a/apps/api/src/services/__tests__/EventService.test.ts
+++ b/apps/api/src/services/__tests__/EventService.test.ts
@@ -599,6 +599,197 @@ describe('EventService', () => {
     });
   });
 
+  // ========================================
+  // FIELD DISCOVERY
+  // ========================================
+  describe('getAvailableEventFields', () => {
+    it('should discover fields from event data', async () => {
+      const contact = await factories.createContact({projectId});
+
+      // Create events with various fields
+      await EventService.trackEvent(projectId, 'email.opened', contact.id, undefined, {
+        subject: 'Welcome',
+        from: 'hello@example.com',
+        openedAt: new Date().toISOString(),
+      });
+
+      await EventService.trackEvent(projectId, 'email.opened', contact.id, undefined, {
+        subject: 'Newsletter',
+        from: 'news@example.com',
+        isFirstOpen: true,
+        opens: 1,
+      });
+
+      const fields = await EventService.getAvailableEventFields(projectId, 'email.opened');
+
+      expect(fields).toContain('event.subject');
+      expect(fields).toContain('event.from');
+      expect(fields).toContain('event.openedAt');
+      expect(fields).toContain('event.isFirstOpen');
+      expect(fields).toContain('event.opens');
+      expect(fields).toHaveLength(5);
+    });
+
+    it('should filter fields by event name', async () => {
+      const contact = await factories.createContact({projectId});
+
+      // Create email.opened events
+      await EventService.trackEvent(projectId, 'email.opened', contact.id, undefined, {
+        subject: 'Test',
+        openedAt: new Date().toISOString(),
+      });
+
+      // Create email.clicked events
+      await EventService.trackEvent(projectId, 'email.clicked', contact.id, undefined, {
+        subject: 'Test',
+        link: 'https://example.com',
+        clickedAt: new Date().toISOString(),
+      });
+
+      // Get fields for email.opened only
+      const openedFields = await EventService.getAvailableEventFields(projectId, 'email.opened');
+
+      expect(openedFields).toContain('event.subject');
+      expect(openedFields).toContain('event.openedAt');
+      expect(openedFields).not.toContain('event.link');
+      expect(openedFields).not.toContain('event.clickedAt');
+    });
+
+    it('should return all event fields when no event name specified', async () => {
+      const contact = await factories.createContact({projectId});
+
+      await EventService.trackEvent(projectId, 'email.opened', contact.id, undefined, {
+        openedAt: new Date().toISOString(),
+      });
+
+      await EventService.trackEvent(projectId, 'email.clicked', contact.id, undefined, {
+        link: 'https://example.com',
+      });
+
+      const allFields = await EventService.getAvailableEventFields(projectId);
+
+      expect(allFields).toContain('event.openedAt');
+      expect(allFields).toContain('event.link');
+    });
+
+    it('should return empty array when no events exist', async () => {
+      const fields = await EventService.getAvailableEventFields(projectId, 'nonexistent.event');
+
+      expect(fields).toHaveLength(0);
+    });
+
+    it('should ignore events with null data', async () => {
+      const contact = await factories.createContact({projectId});
+
+      // Event without data
+      await EventService.trackEvent(projectId, 'simple.event', contact.id);
+
+      // Event with data
+      await EventService.trackEvent(projectId, 'simple.event', contact.id, undefined, {
+        field1: 'value1',
+      });
+
+      const fields = await EventService.getAvailableEventFields(projectId, 'simple.event');
+
+      expect(fields).toEqual(['event.field1']);
+    });
+
+    it('should handle nested field structures', async () => {
+      const contact = await factories.createContact({projectId});
+
+      await EventService.trackEvent(projectId, 'complex.event', contact.id, undefined, {
+        user: {
+          name: 'John',
+          email: 'john@example.com',
+        },
+        metadata: {
+          source: 'web',
+        },
+      });
+
+      const fields = await EventService.getAvailableEventFields(projectId, 'complex.event');
+
+      // Should return top-level keys
+      expect(fields).toContain('event.user');
+      expect(fields).toContain('event.metadata');
+    });
+
+    it('should deduplicate fields across multiple events', async () => {
+      const contact = await factories.createContact({projectId});
+
+      // Create 5 events with same fields
+      for (let i = 0; i < 5; i++) {
+        await EventService.trackEvent(projectId, 'test.event', contact.id, undefined, {
+          field1: `value${i}`,
+          field2: `value${i}`,
+        });
+      }
+
+      const fields = await EventService.getAvailableEventFields(projectId, 'test.event');
+
+      expect(fields).toEqual(['event.field1', 'event.field2']);
+    });
+
+    it('should respect 100 event sample limit for performance', async () => {
+      const contact = await factories.createContact({projectId});
+
+      // Create 150 events with different fields
+      for (let i = 0; i < 150; i++) {
+        await EventService.trackEvent(projectId, 'test.event', contact.id, undefined, {
+          [`field${i}`]: `value${i}`,
+        });
+      }
+
+      const fields = await EventService.getAvailableEventFields(projectId, 'test.event');
+
+      // Should sample only last 100 events (most recent)
+      // So we should see field50-field149 (100 fields)
+      expect(fields.length).toBeLessThanOrEqual(100);
+    });
+
+    it('should return fields in alphabetical order', async () => {
+      const contact = await factories.createContact({projectId});
+
+      await EventService.trackEvent(projectId, 'test.event', contact.id, undefined, {
+        zebra: 'last',
+        apple: 'first',
+        middle: 'middle',
+      });
+
+      const fields = await EventService.getAvailableEventFields(projectId, 'test.event');
+
+      expect(fields).toEqual(['event.apple', 'event.middle', 'event.zebra']);
+    });
+
+    it('should handle email event data structure', async () => {
+      const contact = await factories.createContact({projectId});
+      const email = await factories.createEmail(projectId, contact.id);
+
+      // Simulate actual email.sent event data
+      await EventService.trackEvent(projectId, 'email.sent', contact.id, email.id, {
+        subject: 'Welcome Email',
+        from: 'hello@example.com',
+        fromName: 'Example Team',
+        messageId: 'msg-123',
+        templateId: 'tpl-456',
+        campaignId: null,
+        sourceType: 'TRANSACTIONAL',
+        sentAt: new Date().toISOString(),
+      });
+
+      const fields = await EventService.getAvailableEventFields(projectId, 'email.sent');
+
+      expect(fields).toContain('event.subject');
+      expect(fields).toContain('event.from');
+      expect(fields).toContain('event.fromName');
+      expect(fields).toContain('event.messageId');
+      expect(fields).toContain('event.templateId');
+      expect(fields).toContain('event.campaignId');
+      expect(fields).toContain('event.sourceType');
+      expect(fields).toContain('event.sentAt');
+    });
+  });
+
   describe('Event Data - Persistent vs Non-Persistent', () => {
     it('should store all event data (persistent + non-persistent) in event record', async () => {
       const contact = await factories.createContact({projectId});
diff --git a/apps/api/src/services/__tests__/WorkflowExecutionService.integration.test.ts b/apps/api/src/services/__tests__/WorkflowExecutionService.integration.test.ts
index dcb3b16..7d10564 100644
--- a/apps/api/src/services/__tests__/WorkflowExecutionService.integration.test.ts
+++ b/apps/api/src/services/__tests__/WorkflowExecutionService.integration.test.ts
@@ -954,4 +954,299 @@ describe('WorkflowExecutionService - Integration Tests', () => {
       expect(savedContact?.data).not.toHaveProperty('trackingUrl');
     });
   });
+
+  // ========================================
+  // EVENT DATA IN WORKFLOW CONDITIONS
+  // ========================================
+  describe('Event Data in Workflow Conditions', () => {
+    it('should evaluate conditions using event.* fields', async () => {
+      const contact = await factories.createContact({projectId});
+      const workflow = await factories.createWorkflow({projectId});
+
+      const triggerStep = await prisma.workflowStep.findFirst({
+        where: {workflowId: workflow.id, type: 'TRIGGER'},
+      });
+
+      // Create condition step that checks event data
+      const conditionStep = await prisma.workflowStep.create({
+        data: {
+          workflowId: workflow.id,
+          type: WorkflowStepType.CONDITION,
+          name: 'Check if first open',
+          position: {x: 100, y: 0},
+          config: {
+            field: 'event.isFirstOpen',
+            operator: 'equals',
+            value: true, // Use boolean, not string
+          } as Prisma.InputJsonValue,
+        },
+      });
+
+      const yesStep = await prisma.workflowStep.create({
+        data: {
+          workflowId: workflow.id,
+          type: WorkflowStepType.EXIT,
+          name: 'First Open',
+          position: {x: 200, y: 0},
+          config: {reason: 'first_open'} as Prisma.InputJsonValue,
+        },
+      });
+
+      const noStep = await prisma.workflowStep.create({
+        data: {
+          workflowId: workflow.id,
+          type: WorkflowStepType.EXIT,
+          name: 'Not First Open',
+          position: {x: 200, y: 100},
+          config: {reason: 'not_first_open'} as Prisma.InputJsonValue,
+        },
+      });
+
+      // Connect steps
+      await prisma.workflowTransition.create({
+        data: {fromStepId: triggerStep!.id, toStepId: conditionStep.id},
+      });
+      await prisma.workflowTransition.create({
+        data: {fromStepId: conditionStep.id, toStepId: yesStep.id, condition: {branch: 'yes'} as Prisma.InputJsonValue},
+      });
+      await prisma.workflowTransition.create({
+        data: {fromStepId: conditionStep.id, toStepId: noStep.id, condition: {branch: 'no'} as Prisma.InputJsonValue},
+      });
+
+      // Create execution with event data
+      const execution = await prisma.workflowExecution.create({
+        data: {
+          workflowId: workflow.id,
+          contactId: contact.id,
+          status: WorkflowExecutionStatus.RUNNING,
+          currentStepId: triggerStep!.id,
+          context: {
+            subject: 'Welcome Email',
+            from: 'hello@example.com',
+            isFirstOpen: true,
+            openedAt: new Date().toISOString(),
+          } as Prisma.InputJsonValue,
+        },
+      });
+
+      // Process the workflow
+      await WorkflowExecutionService.processStepExecution(execution.id, triggerStep!.id);
+
+      // Verify it followed YES branch (first open)
+      const completedExecution = await prisma.workflowExecution.findUnique({
+        where: {id: execution.id},
+        include: {stepExecutions: true},
+      });
+
+      expect(completedExecution?.status).toBe(WorkflowExecutionStatus.COMPLETED);
+      expect(completedExecution?.exitReason).toBe('first_open');
+    });
+
+    it('should evaluate conditions using event.subject field', async () => {
+      const contact = await factories.createContact({projectId});
+      const workflow = await factories.createWorkflow({projectId});
+
+      const triggerStep = await prisma.workflowStep.findFirst({
+        where: {workflowId: workflow.id, type: 'TRIGGER'},
+      });
+
+      const conditionStep = await prisma.workflowStep.create({
+        data: {
+          workflowId: workflow.id,
+          type: WorkflowStepType.CONDITION,
+          name: 'Check subject',
+          position: {x: 100, y: 0},
+          config: {
+            field: 'event.subject',
+            operator: 'contains',
+            value: 'Welcome',
+          } as Prisma.InputJsonValue,
+        },
+      });
+
+      const exitStep = await prisma.workflowStep.create({
+        data: {
+          workflowId: workflow.id,
+          type: WorkflowStepType.EXIT,
+          name: 'Done',
+          position: {x: 200, y: 0},
+          config: {reason: 'matched'} as Prisma.InputJsonValue,
+        },
+      });
+
+      await prisma.workflowTransition.create({
+        data: {fromStepId: triggerStep!.id, toStepId: conditionStep.id},
+      });
+      await prisma.workflowTransition.create({
+        data: {fromStepId: conditionStep.id, toStepId: exitStep.id, condition: {branch: 'yes'} as Prisma.InputJsonValue},
+      });
+
+      const execution = await prisma.workflowExecution.create({
+        data: {
+          workflowId: workflow.id,
+          contactId: contact.id,
+          status: WorkflowExecutionStatus.RUNNING,
+          currentStepId: triggerStep!.id,
+          context: {
+            subject: 'Welcome to Plunk!',
+            from: 'team@plunk.com',
+          } as Prisma.InputJsonValue,
+        },
+      });
+
+      await WorkflowExecutionService.processStepExecution(execution.id, triggerStep!.id);
+
+      const completedExecution = await prisma.workflowExecution.findUnique({
+        where: {id: execution.id},
+      });
+
+      expect(completedExecution?.status).toBe(WorkflowExecutionStatus.COMPLETED);
+      expect(completedExecution?.exitReason).toBe('matched');
+    });
+
+    it('should handle numeric event fields in conditions', async () => {
+      const contact = await factories.createContact({projectId});
+      const workflow = await factories.createWorkflow({projectId});
+
+      const triggerStep = await prisma.workflowStep.findFirst({
+        where: {workflowId: workflow.id, type: 'TRIGGER'},
+      });
+
+      const conditionStep = await prisma.workflowStep.create({
+        data: {
+          workflowId: workflow.id,
+          type: WorkflowStepType.CONDITION,
+          name: 'Check opens count',
+          position: {x: 100, y: 0},
+          config: {
+            field: 'event.opens',
+            operator: 'greaterThan',
+            value: '3',
+          } as Prisma.InputJsonValue,
+        },
+      });
+
+      const exitStep = await prisma.workflowStep.create({
+        data: {
+          workflowId: workflow.id,
+          type: WorkflowStepType.EXIT,
+          name: 'Done',
+          position: {x: 200, y: 0},
+          config: {reason: 'engaged'} as Prisma.InputJsonValue,
+        },
+      });
+
+      await prisma.workflowTransition.create({
+        data: {fromStepId: triggerStep!.id, toStepId: conditionStep.id},
+      });
+      await prisma.workflowTransition.create({
+        data: {fromStepId: conditionStep.id, toStepId: exitStep.id, condition: {branch: 'yes'} as Prisma.InputJsonValue},
+      });
+
+      const execution = await prisma.workflowExecution.create({
+        data: {
+          workflowId: workflow.id,
+          contactId: contact.id,
+          status: WorkflowExecutionStatus.RUNNING,
+          currentStepId: triggerStep!.id,
+          context: {
+            subject: 'Newsletter',
+            opens: 5,
+          } as Prisma.InputJsonValue,
+        },
+      });
+
+      await WorkflowExecutionService.processStepExecution(execution.id, triggerStep!.id);
+
+      const completedExecution = await prisma.workflowExecution.findUnique({
+        where: {id: execution.id},
+      });
+
+      expect(completedExecution?.status).toBe(WorkflowExecutionStatus.COMPLETED);
+      expect(completedExecution?.exitReason).toBe('engaged');
+    });
+  });
+
+  // ========================================
+  // EVENT DATA IN WEBHOOK CALLS
+  // ========================================
+  describe('Event Data in Webhook Calls', () => {
+    it('should include event data in webhook payload', async () => {
+      // Mock fetch to capture webhook calls
+      const mockFetch = vi.fn(async () => ({
+        ok: true,
+        status: 200,
+        text: async () => JSON.stringify({success: true}),
+      }));
+      global.fetch = mockFetch as any;
+
+      const contact = await factories.createContact({
+        projectId,
+        email: 'test@example.com',
+      });
+      const workflow = await factories.createWorkflow({projectId});
+
+      const triggerStep = await prisma.workflowStep.findFirst({
+        where: {workflowId: workflow.id, type: 'TRIGGER'},
+      });
+
+      const webhookStep = await prisma.workflowStep.create({
+        data: {
+          workflowId: workflow.id,
+          type: WorkflowStepType.WEBHOOK,
+          name: 'Send Webhook',
+          position: {x: 100, y: 0},
+          config: {
+            url: 'https://webhook.example.com/test',
+            method: 'POST',
+          } as Prisma.InputJsonValue,
+        },
+      });
+
+      await prisma.workflowTransition.create({
+        data: {fromStepId: triggerStep!.id, toStepId: webhookStep.id},
+      });
+
+      const execution = await prisma.workflowExecution.create({
+        data: {
+          workflowId: workflow.id,
+          contactId: contact.id,
+          status: WorkflowExecutionStatus.RUNNING,
+          currentStepId: triggerStep!.id,
+          context: {
+            subject: 'Welcome Email',
+            from: 'hello@example.com',
+            messageId: 'msg-123',
+            isFirstOpen: true,
+            openedAt: '2024-01-15T10:00:00Z',
+          } as Prisma.InputJsonValue,
+        },
+      });
+
+      await WorkflowExecutionService.processStepExecution(execution.id, triggerStep!.id);
+
+      // Verify webhook was called with event data
+      expect(mockFetch).toHaveBeenCalledWith(
+        'https://webhook.example.com/test',
+        expect.objectContaining({
+          method: 'POST',
+          body: expect.stringContaining('"event"'),
+        }),
+      );
+
+      // Parse the body to verify event data structure
+      const callArgs = mockFetch.mock.calls[0];
+      const body = JSON.parse(callArgs[1].body);
+
+      expect(body.event).toMatchObject({
+        subject: 'Welcome Email',
+        from: 'hello@example.com',
+        messageId: 'msg-123',
+        isFirstOpen: true,
+        openedAt: '2024-01-15T10:00:00Z',
+      });
+
+      expect(body.contact.email).toBe('test@example.com');
+    });
+  });
 });
diff --git a/apps/web/next-env.d.ts b/apps/web/next-env.d.ts
index 7996d35..1970904 100644
--- a/apps/web/next-env.d.ts
+++ b/apps/web/next-env.d.ts
@@ -1,6 +1,6 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-import "./.next/dev/types/routes.d.ts";
+import "./.next/types/routes.d.ts";
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/pages/api-reference/config/typescript for more information.
diff --git a/apps/web/src/pages/workflows/[id].tsx b/apps/web/src/pages/workflows/[id].tsx
index 6764533..755945b 100644
--- a/apps/web/src/pages/workflows/[id].tsx
+++ b/apps/web/src/pages/workflows/[id].tsx
@@ -654,14 +654,21 @@ function AddStepDialog({open, onOpenChange, workflowId, onSuccess}: AddStepDialo
   const [isSubmitting, setIsSubmitting] = useState(false);
 
   const {data: templatesData} = useSWR<{templates: Template[]}>('/templates?pageSize=100');
+  const {data: workflow} = useSWR<WorkflowWithDetails>(workflowId ? `/workflows/${workflowId}` : null);
 
-  // Fetch available contact fields when dialog opens and type is CONDITION
+  // Fetch available fields when dialog opens and type is CONDITION
   useEffect(() => {
     const fetchAvailableFields = async () => {
-      if (type === 'CONDITION' && open) {
+      if (type === 'CONDITION' && open && workflow) {
         setLoadingFields(true);
         try {
-          const response = await network.fetch<{fields: string[]}>('GET', '/contacts/fields');
+          // Get event name from workflow trigger config
+          const triggerConfig = workflow.triggerConfig as {eventName?: string} | null;
+          const eventName = triggerConfig?.eventName;
+
+          // Pass eventName as query param to filter event fields
+          const url = eventName ? `/workflows/fields?eventName=${encodeURIComponent(eventName)}` : '/workflows/fields';
+          const response = await network.fetch<{fields: string[]}>('GET', url);
           setAvailableFields(response.fields);
 
           // Set default field if available
@@ -679,7 +686,7 @@ function AddStepDialog({open, onOpenChange, workflowId, onSuccess}: AddStepDialo
 
     void fetchAvailableFields();
     // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [type, open]);
+  }, [type, open, workflow]);
 
   const handleSubmit = async (e: React.FormEvent) => {
     e.preventDefault();
@@ -1162,14 +1169,21 @@ function EditStepDialog({step, workflowId, open, onOpenChange, onSuccess}: EditS
   const [exitReason, setExitReason] = useState(String(config?.reason || 'completed'));
 
   const {data: templatesData} = useSWR<{templates: Template[]}>('/templates?pageSize=100');
+  const {data: workflow} = useSWR<WorkflowWithDetails>(workflowId ? `/workflows/${workflowId}` : null);
 
   // Fetch available contact fields when dialog opens and type is CONDITION
   useEffect(() => {
     const fetchAvailableFields = async () => {
-      if (step.type === 'CONDITION' && open) {
+      if (step.type === 'CONDITION' && open && workflow) {
         setLoadingFields(true);
         try {
-          const response = await network.fetch<{fields: string[]}>('GET', '/contacts/fields');
+          // Get event name from workflow trigger config
+          const triggerConfig = workflow.triggerConfig as {eventName?: string} | null;
+          const eventName = triggerConfig?.eventName;
+
+          // Pass eventName as query param to filter event fields
+          const url = eventName ? `/workflows/fields?eventName=${encodeURIComponent(eventName)}` : '/workflows/fields';
+          const response = await network.fetch<{fields: string[]}>('GET', url);
           setAvailableFields(response.fields);
         } catch (error) {
           console.error('Failed to fetch available fields:', error);
@@ -1181,7 +1195,7 @@ function EditStepDialog({step, workflowId, open, onOpenChange, onSuccess}: EditS
     };
 
     void fetchAvailableFields();
-  }, [step.type, open]);
+  }, [step.type, open, workflow, workflowId]);
 
   const handleSubmit = async (e: React.FormEvent) => {
     e.preventDefault();