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Plunk logo

Open-Source Transactional Email Platform

Starting price
$0.001per email
Pricing
Free plan
Social media
@useplunk

About Plunk

Plunk is an open-source, self-hosted transactional email platform that handles transactional emails, marketing campaigns, and automated workflows from a single contact list. It targets developers, product and marketing teams who want full control, no per-contact limits, and flat pricing at $0.001 per email.

Plunk screenshot

Key Features

Architected for observability and control, Plunk lets you trigger actions from code, build end-to-end flows, and keep a single, up-to-date contact history. This setup matters when you need predictable deliverability and auditable workflows:

Inbound Email

Add one MX record and every address at your domain starts receiving. Replies become contacts and trigger workflows like any other event.

Workflows

Visual editor to design end-to-end automation; triggers fire from your app events and you see the full workflow on the canvas.

Segments

Audiences stay current by re-running a query each time you send; tomorrow’s campaign targets the updated segment.

SMTP

Connect any SMTP client or library to Plunk without modifying your app.

Summary

Best for engineering teams, platform teams, and growth/marketing squads running transactional emails and automated workflows at scale.

Plans and prices as listed on useplunk.com as of Aug 31, 2026.

Free plan

$0.00 / monthly

  • 1,000 emails per month
  • Unlimited contacts
  • No credit card required
  • Transactional emails
  • Workflow automation
  • Campaign broadcasts
  • Custom domains
  • Click & open tracking
  • Plunk branding on emails

Pay as you grow

$0.001 / per email

  • Everything in Free
  • No Plunk branding
  • Monthly spend cap
  • Unlimited emails

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