Stalwart Mail Server

Modernize your mail server

Self-hosting your mail server has been notoriously difficult. Not anymore! Stalwart is a scalable, secure and robust open-source mail server software designed for the 21st century.

Key features


Designed around JMAP, a modern protocol for accessing e-mails and other data.

Built to scale

Scales to millions of users thanks to FoundationDB.

Powered by Rust

Incredibly fast while ensuring memory safety. No runtimes or garbage collectors.

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Stalwart JMAP

Stalwart JMAP is an open-source JSON Meta Application Protocol server designed to be robust, secure and scalable.

  • Rock solid.

  • Secure. Written in Rust.

  • Scalable and fault-tolerant.


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Stalwart IMAP

Stalwart IMAP is an open-source Internet Message Access Protocol server with both IMAP4rev2 and IMAP4rev1 support.

  • IMAP4rev2+1 compliant.

  • Supports multiple IMAP4 extensions.

  • Standards Compliant.


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Stalwart SMTP

Stalwart SMTP is a modern SMTP server developed in Rust with a focus on security, speed, and extensive configurability.

  • Built-in DMARC, DKIM, SPF and ARC support.

  • Transport security through DANE and MTA-STS.

  • Configurable rules and Sieve scripting.


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Frequently asked questions

If you have a question that is not listed here you may use the contact form below or write to us on Discord.

You can get help from the community by starting a discussion on Github or Discord. You may also become a sponsor and get support directly from Stalwart Labs Ltd.
Stalwart Mail Server stores all metadata and settings in SQLite or in FoundationDB, a high performance distributed database. E-mail messages are stored separately from metadata, directly in the file system using Maildir or alternatively on the S3-storage of your choice.