# Stalwart — All-in-One Mail and Collaboration Server in Rust

> Stalwart is a self-hosted mail server written in Rust that supports JMAP, IMAP4, POP3, SMTP, CalDAV, CardDAV, and WebDAV in a single binary with built-in spam filtering and encryption.

## Install

Save in your project root:

# Stalwart — All-in-One Mail and Collaboration Server in Rust

## Quick Use
```bash
# Install via Docker
docker run -d -p 443:443 -p 25:25 -p 587:587 -p 993:993 
  -v stalwart-data:/opt/stalwart-mail 
  --name stalwart stalwartlabs/stalwart:latest
# Open https://localhost/login — set admin credentials on first run
```

## Introduction
Stalwart is an open-source mail and collaboration server written entirely in Rust that combines SMTP, IMAP, JMAP, POP3, CalDAV, CardDAV, and WebDAV into one unified binary. It replaces the traditional stack of Postfix + Dovecot + Rspamd with a single process that is memory-safe, fast, and straightforward to deploy.

## What Stalwart Does
- Sends and receives email via SMTP with DKIM, SPF, DMARC, ARC, and MTA-STS support
- Serves mailboxes over IMAP4, JMAP, and POP3 with full-text search built in
- Provides calendar and contacts sync through CalDAV and CardDAV
- Includes a built-in spam and phishing filter powered by statistical analysis and rules
- Supports file sharing and collaboration via WebDAV

## Architecture Overview
Stalwart compiles to a single statically-linked binary that embeds all protocol handlers, a web administration interface, and a configurable storage backend. It supports RocksDB for embedded single-node setups, PostgreSQL or MySQL for shared deployments, and S3-compatible object storage for blob data. TLS is handled natively with automatic ACME certificate provisioning via Let's Encrypt.

## Self-Hosting & Configuration
- Deploy as a single Docker container or download the pre-built binary for Linux and macOS
- All configuration is managed through the built-in web admin UI or a TOML config file
- Storage backends: RocksDB (default embedded), PostgreSQL, MySQL, or SQLite
- TLS certificates are auto-provisioned via ACME; manual certificate paths are also supported
- DNS records (MX, SPF, DKIM, DMARC) must be configured at your domain registrar

## Key Features
- Single binary replaces an entire mail stack (MTA, MDA, spam filter, groupware)
- Written in Rust for memory safety with no garbage collection pauses
- Built-in full-text search across mailboxes with no external dependency like Solr or Elasticsearch
- JMAP support for modern, fast email clients alongside traditional IMAP4
- Web-based admin console with user management, queue monitoring, and log viewing

## Comparison with Similar Tools
- **Mail-in-a-Box** — Automated Postfix/Dovecot bundle; easier initial setup but less flexible
- **Maddy** — Go-based all-in-one mail server; fewer protocols and no CalDAV/CardDAV
- **Mailcow** — Docker-based Postfix/Dovecot/Rspamd stack; more moving parts to maintain
- **iRedMail** — Script-based installer for traditional mail stack; harder to update components individually
- **Postfix + Dovecot** — The classic combo; proven but requires gluing multiple services together

## FAQ
**Q: Can Stalwart handle multiple domains?**
A: Yes. Stalwart supports unlimited virtual domains, each with independent DKIM keys, catch-all addresses, and per-domain storage quotas.

**Q: Does it include a webmail client?**
A: Stalwart itself does not bundle a webmail UI, but it works with any IMAP or JMAP client. Roundcube and Snappymail are common self-hosted webmail frontends used alongside it.

**Q: How does spam filtering work?**
A: Stalwart includes a built-in spam filter that uses Bayesian classification, DNS blocklists, header analysis, and configurable rules. It does not require an external tool like Rspamd or SpamAssassin.

**Q: What are the hardware requirements?**
A: A VPS with 1 CPU core, 1 GB RAM, and 10 GB disk is sufficient for small deployments with a few hundred mailboxes. Stalwart is lightweight due to its Rust implementation.

## Sources
- https://github.com/stalwartlabs/stalwart
- https://stalw.art/docs/

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Source: https://tokrepo.com/en/workflows/9a641a43-3f0f-11f1-9bc6-00163e2b0d79
Author: AI Open Source