smyile/rustmail repository overview

⁠RustMail

A fast, feature-rich SMTP mail catcher built in Rust. Single binary. Persistent storage. Modern UI. CI-ready.

GitHub: rustmailapp/rustmail⁠ · Docs: docs.rustmail.app⁠

⁠Quick Start

docker run -p 1025:1025 -p 8025:8025 smyile/rustmail:latest

Point your app's SMTP at localhost:1025, then open localhost:8025⁠. Emails show up in real time.

⁠Docker Compose

services:
  rustmail:
    image: smyile/rustmail:latest
    ports:
      - "1025:1025"
      - "8025:8025"
    security_opt:
      - no-new-privileges:true
    volumes:
      - rustmail-data:/data
    restart: unless-stopped

volumes:
  rustmail-data:

⁠Supported Architectures

Multi-arch manifest — Docker automatically pulls the correct image for your platform.

⁠Persistence

The image stores emails at /data/rustmail.db by default. Mount a volume to /data to persist emails across container restarts.

For ephemeral (CI) usage, skip the volume:

docker run -p 1025:1025 -p 8025:8025 -e RUSTMAIL_EPHEMERAL=true smyile/rustmail:latest

⁠Environment Variables

All configuration is done via RUSTMAIL_* environment variables:

⁠Ports

STARTTLS uses the normal SMTP port and is advertised only when both RUSTMAIL_SMTP_TLS_CERT and RUSTMAIL_SMTP_TLS_KEY are set.

⁠Optional STARTTLS

Mount your TLS files read-only and set both environment variables:

docker run \
  -p 1025:1025 -p 8025:8025 \
  -v "$PWD/certs:/certs:ro" \
  -e RUSTMAIL_SMTP_TLS_CERT=/certs/smtp-cert.pem \
  -e RUSTMAIL_SMTP_TLS_KEY=/certs/smtp-key.pem \
  smyile/rustmail:latest

Clients must issue EHLO, then STARTTLS, and then EHLO again after the TLS handshake completes.

⁠Features

• Persistent storage — SQLite-backed, emails survive restarts
• Full-text search — FTS5 across subject, body, sender, and recipients
• Real-time updates — WebSocket pushes new emails to the UI instantly
• Modern UI — dark-mode-first, looks and feels like a real email client
• DKIM/SPF/DMARC/ARC display — parses authentication headers with color-coded badges
• REST assertion endpoints — GET /api/v1/assert/count?min=1&subject=Welcome
• Webhook notifications — fire-and-forget POST on new email
• Email release — forward captured emails to a real SMTP server
• Export — download as EML or JSON
• Retention policies — auto-purge by age or count

⁠Image Details

• Base image: alpine:3.21
• Runs as: non-root user rustmail
• Healthcheck: built-in (HTTP check every 30s)
• Volume: /data
• Security: no-new-privileges recommended

⁠License

Licensed under either of MIT⁠ or Apache 2.0⁠, at your option.