Mox is a modern email server focused on simplicity, privacy, and security. It handles IMAP and SMTP with built-in TLS and features like efficient email delivery, minimal configuration, and advanced spam protection. Mox emphasizes ease of use and aims to provide a reliable mail server solution for both individuals and small organizations.
Key Features
- Quick and easy to start/maintain mail server, for your own domain(s).
- SMTP (with extensions) for receiving, submitting and delivering email.
- IMAP4 (with extensions) for giving email clients access to email.
- Webmail for reading/sending email from the browser.
- SPF/DKIM/DMARC for authenticating messages/delivery, also DMARC aggregate reports.
- Reputation tracking, learning (per user) host-, domain- and sender address-based reputation from (Non-)Junk email classification.
- Bayesian spam filtering that learns (per user) from (Non-)Junk email.
- Slowing down senders with no/low reputation or questionable email content (similar to greylisting). Rejected emails are stored in a mailbox called Rejects for a short period, helping with misclassified legitimate synchronous signup/login/transactional emails.
- Internationalized email, with unicode in email address usernames ("localparts"), and in domain names (IDNA).
- Automatic TLS with ACME, for use with Let's Encrypt and other CA's.
- DANE and MTA-STS for inbound and outbound delivery over SMTP with STARTTLS, including REQUIRETLS and with incoming/outgoing TLSRPT reporting.
- Web admin interface that helps you set up your domains, accounts and list aliases (instructions to create DNS records, configure SPF/DKIM/DMARC/TLSRPT/MTA-STS), for status information, and modifying the configuration file.
- Account autodiscovery (with SRV records, Microsoft-style, Thunderbird-style, and Apple device management profiles) for easy account setup (though client support is limited).
- Webserver with serving static files and forwarding requests (reverse proxy), so port 443 can also be used to serve websites.
- Simple HTTP/JSON API for sending transaction email and receiving delivery events and incoming messages (webapi and webhooks).
- Prometheus metrics and structured logging for operational insight.
- "mox localserve" subcommand for running mox locally for email-related testing/developing, including pedantic mode.
- Most non-server Go packages mox consists of are written to be reusable.