Plunk

Plunk

Open-source email platform — transactional sends, campaigns, and automations at $0.001 per email, self-hostable.

Email Marketingfreemium
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What is Plunk?
Plunk is an open-source email platform that bundles transactional email, marketing campaigns, and event-driven automations into one lightweight product. Its pitch is radical simplicity and pricing honesty: the hosted version charges $0.001 per email with no contact limits, so you pay for what you send rather than how big your list is. Developers trigger emails and track events through a small REST API and SDKs, then build automations that react to those events — a sign-up event can kick off an onboarding sequence without extra code. Because the entire platform is open source, teams with compliance needs or cost constraints can self-host Plunk on their own infrastructure with Docker. For indie hackers and small SaaS products, it's one of the cheapest credible ways to run all product email.
Key Features

Transactional email, campaigns, and automations in one product

Usage-based pricing: $0.001 per email with no contact limits

Fully open source and self-hostable with Docker

Event tracking API that triggers automation sequences

Simple REST API and SDKs for quick integration

Use Cases
  • Sending all email for an indie SaaS at minimal cost
  • Self-hosting the email stack for data control
  • Event-triggered onboarding and engagement sequences
  • Replacing separate campaign and transactional tools with one
How to Use Plunk
  1. 1Sign up on the hosted version or self-host with Docker
  2. 2Verify your domain and grab an API key
  3. 3Send transactional emails and track events via the API
  4. 4Create automations and campaigns on top of tracked events
Best For
Indie hackers and bootstrapped SaaS foundersDevelopers who want open-source email infrastructureCost-sensitive products with large contact lists
FAQ

How much does Plunk cost?

The hosted version charges $0.001 per email sent with no contact limits. Self-hosting the open-source version is free apart from your infrastructure costs.

Is Plunk open source?

Yes. The full platform is open source on GitHub and can be self-hosted with Docker, including transactional sending, campaigns, and automations.

How does Plunk compare to Resend?

Resend offers a more polished developer experience and React Email templates, while Plunk covers campaigns and automations too, costs less at volume, and can be self-hosted.

Tags
Email MarketingOpen SourceAPI
Quick Info
CategoryEmail Marketing
Pricingfreemium
Platformsweb, api
Websiteuseplunk.com

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