The open‑source
email platform.
Transactional email, marketing campaigns and workflows in one AGPL-3.0 codebase. Run it on your own servers, or let us run it for you in the EU.
useplunk/plunk
One codebase
Plunk Cloud
Managed, hosted in Germany
Self-hosted
Your server, your SES account
$ docker compose up -dWhat is in the repository
One platform, not three projects
Transactional email, campaigns and workflows share one contact list. Most open-source email tools cover only one of these.
GitHub
useplunk/plunk
AGPL-3.0, on GitHub
The full platform is in one public repository: API, dashboard, SMTP server and this website. No license fee to run it.
One Docker Compose file
Self-hosting starts Plunk, PostgreSQL, Redis and MinIO, and sends through your own Amazon SES account.
Also included
REST API and SMTP
Send from any language, or point an existing app at the SMTP server.
Visual editor
Build templates and campaigns without writing HTML.
Segments
Dynamic audiences from contact fields and events.
Inbound email
Receive email and start workflows from it.
Unlimited contacts
Billing, when there is any, is per email sent.
MCP server
Let AI agents send email and manage contacts.
Open-source email tools, compared
Each project is good at something different. This is what each one is built for.
| Project | Built for | Language | License | Official hosting |
|---|---|---|---|---|
| Plunk | Transactional email, campaigns and workflows | TypeScript | AGPL-3.0 | Yes, in the EU |
| listmonk | Newsletters and mailing lists | Go | AGPL-3.0 | No |
| Mautic | Marketing automation suite | PHP | GPL-3.0 | Through third parties |
| phpList | Newsletter management | PHP | AGPL-3.0 | Yes |
| useSend | Email API on Amazon SES | TypeScript | AGPL-3.0 | Yes |
Looking at a hosted tool instead? See how Plunk compares to useSend, Resend alternatives and Mailchimp alternatives.
Frequently asked questions
Run the same code, without running servers.
Start on the free plan with 1,000 emails a month, no credit card needed. When you need more, every email is $0.001, with unlimited contacts and every feature included.