the open source movement

Replace Gmail.

9 open source alternatives, ranked by health. We re-check every project weekly, so you don’t migrate to something abandoned.

Ranked by health

  1. docker-mailserverContainerized mail server bundling SMTP, IMAP, spam and virus filtering configured through files.★ 19k MIT Shell self-host
  2. BillionMailSelf-hosted mail server, newsletter and email marketing platform.★ 16k AGPL-3.0 Go self-host
  3. Mail-in-a-BoxOne-command setup that turns an Ubuntu server into a complete mail server with webmail, contacts and calendar.★ 15k CC0-1.0 (public domain) Python self-host
  4. mailcowDockerized mail server suite with webmail, groupware, spam filtering and admin UI.★ 14k GPL-3.0 JavaScript self-host
  5. MailuDocker-based mail server bundling SMTP, IMAP, spam filtering, webmail and an admin interface.★ 7.5k MIT Python self-host
  6. MoxAll-in-one mail server with SMTP, IMAP, spam filtering, automatic TLS and built-in webmail.★ 5.9k MIT Go self-host
  7. ModoboaMail hosting platform with a web admin, webmail, calendar and contacts on Postfix and Dovecot.★ 3.5k ISC Python self-host
  8. SOGoGroupware server with webmail, calendars and address books over IMAP, CalDAV and CardDAV.★ 2.2k GPL-2.0 Objective-C self-host
  9. iRedMailInstaller that sets up a complete mail server on Linux or BSD with webmail, spam filtering and admin tools.★ 1.8k GPL-3.0 Shell self-host
How the ranking works

Health blends commit recency, release cadence, issue throughput, contributor breadth and star growth. Stars are shown but never ranked on. The full method.