Hedwig

Hedwig - A high-performance, minimalist SMTP server implemented in Rust.

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Features

• Async SMTP relay with persistent filesystem queue
• DKIM signing (RSA and Ed25519)
• MTA-STS (RFC 8461) — automatic TLS policy enforcement for outbound delivery
• SMTP authentication (PLAIN, LOGIN, CRAM-MD5; multiple users)
• TLS/STARTTLS support with multiple listeners
• Per-domain rate limiting
• Prometheus metrics and health checks
• Domain-based sender/recipient filtering

Docs

Documentation lives at https://hedwig.sarat.dev

Install (recommended)

Download the latest release binary from GitHub Releases:

curl -L -o hedwig.zip https://github.com/iamd3vil/hedwig/releases/download/v0.5.2/hedwig-v0.5.2-linux-x86_64.zip
unzip hedwig.zip
chmod +x hedwig

Checksums:

https://github.com/iamd3vil/hedwig/releases/download/v0.5.2/checksums.txt

Build from source

git clone https://github.com/iamd3vil/hedwig.git
cd hedwig
cargo build --release

License

AGPL v3. See LICENSE.