Self-hosted alternatives to Postmark
Want transactional email delivery without handing your data to Postmark? These 6 self-hosted apps run on your own server (most are open source; licenses are listed below). Cheapest estimated hosting starts at about $3.5/month.
About Postmark: Transactional email delivery service.
| App | Health | Stars | License | Docker | RAM (est.) | From |
|---|---|---|---|---|---|---|
| Haraka | Active | 5.6k | MIT | – | 1 GB | $5/mo |
| OpenSMTPD | Active | 586 | ISC | – | 512 MB | $3.5/mo |
| chasquid | Unknown | – | Apache-2.0 | – | 512 MB | $3.5/mo |
| Courier MTA | Unknown | – | GPL-3.0 | – | 512 MB | $3.5/mo |
| EmailRelay | Unknown | – | GPL-3.0 | – | 512 MB | $3.5/mo |
| Sendy | Unknown | – | ⊘ Proprietary | – | 1 GB | $5/mo |
The options in detail
1. Haraka
Fast, highly extensible, and event driven SMTP server.
Active Last commit 2026-11-03. Latest release v3.3.5 (2026-10-17). Needs roughly 1 GB RAM. How to run it →
2. OpenSMTPD
Secure SMTP server implementation from the OpenBSD project.
Active Last commit 2026-11-03. Latest release 7.9.0p0 (2026-09-13). Needs roughly 512 MB RAM. How to run it →
3. chasquid
SMTP (email) server with a focus on simplicity, security, and ease of operation.
Unknown Needs roughly 512 MB RAM. How to run it →
4. Courier MTA
Fast, scalable, enterprise mail/groupware server providing ESMTP, IMAP, POP3, webmail, mailing list, basic web-based calendaring and scheduling services.
Unknown Needs roughly 512 MB RAM. How to run it →
5. EmailRelay
Small and easy to configure SMTP and POP3 server for Windows and Linux.
Unknown Needs roughly 512 MB RAM. How to run it →
6. Sendy
Email newsletter application that lets you send bulk emails via Amazon Simple Email Service (SES) or other SMTP services.
Unknown Needs roughly 1 GB RAM. How to run it →
Why self-host instead of Postmark?
- Own your data — it lives on a server you control, with backups you decide on.
- Predictable cost — a small VPS often replaces per-seat pricing for a whole team or family.
- No lock-in — open-source licenses let you keep running the software even if a vendor disappears.
The trade-off: you are responsible for updates, backups and security. Pick an app marked Active (a commit in the last 90 days) and with Docker support for the easiest ride.
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