Stalwart

TAS Score: S3/3 — D4/5 — A3 / T2 D4 not D5: dual licensing (AGPL-3.0 + proprietary SELv1) — enterprise features gated behind paid license (Q8).

Brief Description

All-in-one mail and collaboration server written in Rust. Supports JMAP, IMAP4, POP3, SMTP, CalDAV, CardDAV, and WebDAV. Single binary — no external databases required. Dual-licensed: AGPL-3.0 (community) and SELv1 (enterprise). 8,400+ GitHub stars. Funded by European NGI programs.

Architectural Role

Communication layer: complete self-hosted email and collaboration infrastructure in a single server. Mail, calendars, contacts, and file storage.

Technical Autonomy

Works without internet — receives and stores mail locally; sending requires internet
Stores data locally — SQLite or FoundationDB, all on your server
Does not require external accounts
Allows data export — standard protocols (IMAP, CalDAV, CardDAV) for migration
Provides offline updates — binary or Docker image, updated manually

Philosophical Assessment (whose.world criteria)

Criterion	Status	Comments
Pause	✅	Stop the process or container. Mail queued by senders per RFC 5321. Resume without data loss.
Exit	✅	Standard protocols (IMAP, CalDAV, CardDAV). Migrate to any server.
Recoverability	✅	Single data directory. SQLite backend. Straightforward backup and restore.
Visibility	✅	Open source (AGPL-3.0). Full source available. Enterprise features visible in code but license-gated.
External Dependencies	✅	No external databases, no external services. Single binary. Optional: Let’s Encrypt.

Rating key: ✅ fully meets · ⚠️ partially meets or requires configuration · ❌ does not meet

Configuration (Minimal)

services:
  stalwart-mail:
    image: stalwartlabs/mail-server:latest
    volumes:
      - ./stalwart-mail:/opt/stalwart-mail
    ports:
      - 443:443
      - 25:25
      - 587:587
      - 465:465
      - 143:143
      - 993:993
      - 4190:4190
    restart: unless-stopped

Admin password logged on first run. Requires DNS configuration (MX, SPF, DKIM, DMARC). Runs comfortably on 512 MB RAM.

Privacy-First Homelab

Alternatives

Alternative	Autonomy	Notes
Mailcow	A3 / T2	More established, larger community, Docker-based, higher resources (4-6 GB RAM)
Gmail	A0 / T0	Zero maintenance, zero ownership

Trajectory

Direction: opening (with caveats)

Actively developed with EU funding (NGI0 Entrust, NGI Zero Core). Approaching v1.0 — feature complete, focusing on performance. AGPL protects community edition. Dual licensing means enterprise features may diverge over time. Worth monitoring.

Signal assessment:

Signal	Status	Evidence
License	➖	AGPL-3.0 (open) + SELv1 (proprietary enterprise). Community edition fully functional.
Feature gating	⚠️	Some features enterprise-only. Sponsors at $5/month get enterprise license.
Self-hosting	✅	Self-hosting is the primary deployment model.
Governance	➖	Stalwart Labs LLC. Open source but corporate-governed. EU funding is positive signal.

Signal key: ✅ opening · ➖ neutral · ⚠️ closing

Sources

Website: https://stalw.art
Documentation: https://stalw.art/docs/get-started
Repository: https://github.com/stalwartlabs/stalwart
Docker image: stalwartlabs/mail-server
Community: https://discord.gg/stalwart