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 out of the box without requiring third-party software.

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. Powered by RocksDB.

  • 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 to JMAP proxy.

  • 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 JMAP stores all metadata and settings in RocksDB, a high performance embedded database for key-value data. RocksDB is used in production systems at various web-scale enterprises including Facebook, Yahoo! and LinkedIn. It has also been adpoted as storage backend by popular SQL and NoSQL databases such as Apache Cassandra, CockroachDB and MySQL. Even though RocksDB can be fully trusted with your information, e-mail messages are stored separately from metadata, directly in the file system to allow quick recovery in case of catastrophic failure.