Mailcow
TAS Score: S3/3 — D5/5 — A3 / T2
Brief Description
Open-source, Docker-based email server suite. Combines Postfix (SMTP), Dovecot (IMAP/POP3), SOGo (webmail/groupware), Rspamd (spam filtering), ClamAV (antivirus), and a web-based admin UI. GPLv3 licensed. 12,400+ GitHub stars.
Architectural Role
Communication layer: complete self-hosted email infrastructure. Handles sending, receiving, filtering, webmail, and administration.
Technical Autonomy
- Works without internet — receives and stores mail locally; sending requires internet (SMTP)
- Stores data locally — all emails, contacts, and calendars on your server
- Does not require external accounts
- Allows data export — standard mbox/Maildir formats; IMAP migration tools available
- Provides offline updates — Docker images can be pulled and applied manually
Philosophical Assessment (whose.world criteria)
| Criterion | Status | Comments |
|---|---|---|
| Pause | ✅ | Stop Docker containers. Mail queued by sending servers per RFC 5321 (retried 3+ days). Resume without data loss. |
| Exit | ✅ | Standard email formats (mbox, Maildir). IMAP-based migration to any server. Your domain, your MX records. |
| Recoverability | ✅ | Full control over backups. Database and mail storage are local. Docker-based architecture makes restoration straightforward. |
| Visibility | ✅ | Fully open source (GPLv3). All components are established open-source projects. |
| External Dependencies | ✅ | Requires domain name and DNS. Optional: ClamAV definitions, Let’s Encrypt. Core works independently. |
Rating key: ✅ fully meets · ⚠️ partially meets or requires configuration · ❌ does not meet
Configuration (Minimal)
cd /opt
git clone https://github.com/mailcow/mailcow-dockerized
cd mailcow-dockerized
./generate_config.sh
docker compose pull
docker compose up -d
Requires DNS configuration (MX, SPF, DKIM, DMARC records) and a VPS with port 25 open. Minimum 4 GB RAM (6 GB recommended with ClamAV).
Related Recipes
Alternatives
| Alternative | Autonomy | Notes |
|---|---|---|
| Stalwart | A3 / T2 | Single binary (Rust), lower resources (~512 MB RAM), newer, JMAP support |
| Gmail | A0 / T0 | Zero maintenance, zero ownership |
Trajectory
Direction: opening
Actively maintained with regular releases. Recently moved Docker images from Docker Hub to GitHub Container Registry — reducing external dependency. Community is active. No signs of license changes or feature gating.
Signal assessment:
| Signal | Status | Evidence |
|---|---|---|
| License | ✅ | GPLv3. No changes. |
| Feature gating | ✅ | All features free. Optional SAL (Stay-Awesome License) is voluntary donation, not required. |
| Self-hosting | ✅ | Self-hosting is the only deployment model. |
| Governance | ✅ | Community-driven. Open issue tracker. Transparent development. |
Signal key: ✅ opening · ➖ neutral · ⚠️ closing
Sources
- Website: https://mailcow.email
- Documentation: https://docs.mailcow.email
- Repository: https://github.com/mailcow/mailcow-dockerized
- Docker image: ghcr.io/mailcow
- Community: https://t.me/mailcow