Open-source alternative
for ConvertKit
ConvertKit is built for creators. Plunk is built for developers who need powerful email automation without the creator-focused bloat. Same automation, better DX, pay-as-you-go.
Pay for Emails, Not Subscribers
Pricing that grows with usage, not list size
Pay per email sent
Pay-as-you-go pricing. Only pay for emails you send, not for subscribers you store.
Unlimited subscribers at no cost Only pay when you actually send Grow your list without price increases
Pay per subscriber count
Monthly subscription based on total subscribers, whether you email them or not.
- Price increases with subscriber count
- Pay even if you don't send emails
- 10K subscribers = $119/month
Built for Developers, Not Creators
Developer-First API
Modern REST API designed for developers. No visual builder complexity, just clean endpoints for sending emails and managing workflows.
Pay-as-you-go Pricing
Only pay for emails sent, not subscribers stored. Grow your list without worrying about tier upgrades or subscription increases.
Open Source
AGPL-3.0 licensed. Inspect the code, contribute features, understand exactly how your emails are sent. ConvertKit is proprietary.
Self-Hostable
Run on your own infrastructure with Docker. Full data control, compliance-ready, cost-optimized for scale. ConvertKit is cloud-only.
5-Minute Setup
Start sending emails in minutes. No form builders to configure, no landing pages to design. Just authenticate and send.
Unlimited Contacts
Store unlimited contacts without penalty. No subscriber tiers, no forced upgrades. Your contact database grows freely.
Feature comparison
Join developers who've switched from ConvertKit to Plunk for better API design and transparent pay-as-you-go pricing.