Mailcow

Self-hosted mail server suite shipped as a set of Docker containers, for running your own email domain instead of a paid mailbox provider.

13.8k stars, 1.9k forks PHP On GitHub since December 2016

Visit website View on GitHub How to run it

Mailcow at a glance

Open sourceYes, GPL-3.0No paid parts in the repository
Health74 of 100Actively developed
Self-hostingDockerCompose file, 18 services
Interface29 languagesIncluding English, German and French
Issue repliesWithin ~4 hoursMedian first reply; 91% of recent issues answered

What is Mailcow?

Mailcow, published as mailcow: dockerized, bundles the parts of an email system into containers that start together through Docker Compose. Its compose file defines 18 services, among them MySQL, Redis and a reverse proxy, so the whole stack runs on one Docker host. The project builds on many existing open-source components, and the README asks users to check that they accept those licenses too. Its web interface is translated into 29 languages. Installation and configuration are covered in the official documentation rather than in the repository README.

Good fit if

  • You want to host mail for your own domains and are comfortable running a Docker host.
  • You prefer one maintained bundle over assembling and wiring mail components by hand.
  • You would like the option of a commercial support contract from the company behind it.

Look elsewhere if

  • You want a lighter containerized mail server with fewer moving parts: docker-mailserver or Mailu.
  • You need a guided setup aimed at individuals on a single box: Mail-in-a-Box.
  • You only need webmail in front of an existing mail server: Roundcube.

Before you adopt it

Every part of mailcow itself is licensed under GPL-3.0, and the repository has no paid parts. The Infrastructure Company GmbH manages the project and owns the mailcow word mark; its Servercow brand sells support contracts and a one-time SAL payment. Recent work is concentrated in one developer, who made almost all of the 135 commits in the last 90 days. Releases are named by month, with 2026-11 the latest. Expect a sizeable stack to keep updated, since 18 containers run side by side.

Drafted with AI from the project's README and repository data, then checked against that data on 7 November 2026. Report a correction

How to run Mailcow yourself

One-click install

Not listed in the app catalogs of Umbrel, YunoHost, TrueNAS, Unraid, CasaOS, Runtipi, Proxmox VE Helper-Scripts and Coolify.

Ways to install

Docker files
Dockerfile or compose file in the repository
Compose file
docker-compose.yml: 18 services (mysql, redis, proxy)
Setup effort
4 of 5, judged from the compose file
Kubernetes
No Helm chart in the repository
Desktop and mobile
No app builds in GitHub releases
Interface languages
29 languages, including English, German, French, Spanish, Portuguese, Dutch, Polish, Russian, Ukrainian and Turkish
Show all 29

Azerbaijani, Bulgarian, Catalan, Chinese, Czech, Danish, Dutch, English, Finnish, French, German, Hungarian, Japanese, Korean, Latvian, Lithuanian, Norwegian Bokmål, Polish, Portuguese, Romanian, Russian, Sinhala, Slovak, Spanish, Swedish, Turkish, Ukrainian, Uzbek, Vietnamese

Install instructions: mailcow.email or the README on GitHub.

Mailcow health: is it still maintained?

74 of 100, actively developed

Release rhythmEvery ~16 daysLatest: 2026-11, 5 November 2026
Issue repliesWithin ~4 hoursMedian first reply; 91% of recent issues answered
Bus factorHigh riskThe most active of 2 authors wrote 96% of recent commits
  • Activity
    133 commits in the last 90 days, the latest on 5 November 2026.
    26 / 30
  • Contributors
    2 people wrote the latest 100 commits; the most active wrote 96% of them.
    4 / 20
  • Releases
    15+ releases in the last 12 months; the latest, 2026-11, on 5 November 2026.
    19 / 20
  • Replies to issues
    Maintainers answered 91% of recent issues, with a median first reply after 4 hours.
    19 / 20
  • Security practices
    OpenSSF Scorecard 5.7 of 10.
    6 / 10

Read from GitHub on 12 November 2026. How the score works

Mailcow security

Security advisories are the vulnerabilities the maintainers disclosed on GitHub, with the versions that fix them; many advisories can mean careful disclosure as much as weak code. OpenSSF Scorecard checks how a project is developed and released: reviews, protected branches, pinned dependencies, signed releases. It does not audit the code itself.

Security advisories32 published5 critical, 14 high; all list a fixed version
OpenSSF Scorecard5.7 of 10How the project is built and released
Security policyYesExplains how to report a vulnerability

Latest advisories

All 32 advisories on GitHub

What each Scorecard check found

  • Binary files10 / 10No compiled binaries checked into the repository
  • Dangerous workflows10 / 10No risky patterns in GitHub Actions
  • License file10 / 10A license file is present
  • Maintained10 / 10Steady commits and issue activity in the last 90 days
  • Packaging10 / 10Releases are published as packages from CI
  • Security policy10 / 10Explains how to report a vulnerability
  • Code review3 / 10Some changes are merged without review
  • Best-practices badge0 / 10No OpenSSF Best Practices badge
  • Fuzzing0 / 10No fuzz testing found
  • Pinned dependencies0 / 10Dependencies are not pinned to fixed versions
  • Static analysis0 / 10No static analysis found
  • Token permissions0 / 10CI tokens have broad write rights

Advisories read from GitHub on 12 November 2026. From the OpenSSF Scorecard of 2 November 2026; checks that do not apply to Mailcow are left out.

Mailcow license: is it open source?

Mailcow uses GPL-3.0, an open-source license approved by the OSI.

  1. December 2016First published on GitHub.
  2. TodayGPL-3.0.

Mailcow for developers

Written in

  • PHP 36%
  • JavaScript 29%
  • Twig 15%
  • CSS 9%
  • Shell 6%
  • Other 5%

Getting involved

Help wanted2Open, labelled “help-wanted”Contributing guideYesCONTRIBUTING.mdOpen issues438On GitHub
Authors, 90 days2Of the latest 100 commits
Donations2 waysGitHub Sponsors, own page

Language shares are GitHub’s count of the code in the repository.

Alternatives to Mailcow

  • docker-mailserverProduction-ready fullstack but simple mail server (SMTP, IMAP, LDAP, Antispam, Antivirus, etc.) running… 80 health · MIT · 19.7k stars
  • MailuInsular email distribution - mail server as Docker images 76 health · MIT · 7.6k stars
  • ModoboaMail hosting made simple 71 health · ISC · 3.5k stars
  • Maddy Mail ServerComposable all-in-one mail server. 73 health · GPL-3.0 · 6.1k stars
  • Stalwart Mail ServerAll-in-one Mail & Collaboration server. Secure, scalable and fluent in every protocol (IMAP, JMAP, SMTP,… 57 health · Unidentified license · 15.9k stars

All 17 projects in Email servers & webmail

Questions about Mailcow

Is Mailcow open source?

Yes. Mailcow is published under GPL-3.0, an OSI-approved open-source license.

Is Mailcow still maintained?

Its health score is 74 of 100 (actively developed). It had 133 commits in the last 90 days, the latest on 5 November 2026, and its latest release came out on 5 November 2026.

How do I run Mailcow?

You can run it with Docker. The README on GitHub has the exact steps.

What is Mailcow written in?

Mailcow is written in PHP (36% of the code), with JavaScript (29%) and Twig (15%), by GitHub’s count of the repository.

What languages is Mailcow available in?

The repository has interface translations for 29 languages, including English, German, French, Spanish, Portuguese, Dutch, Polish and Russian.

What are the alternatives to Mailcow?

Close alternatives in the Email servers & webmail category include docker-mailserver, Mailu, Modoboa.