SMTP Server in Rust with DMARC, Dane, MTA-STS, Sieve, OTEL Support

In plain words

Stalwart SMTP is a mail server written in Rust that handles email authentication through DMARC, DKIM, SPF, and ARC protocols. It provides transport security via DANE and MTA-STS, supports Sieve scripting for message filtering, and offers dynamic configuration rules for customization. Built for security and performance, it is designed for system administrators and organizations managing email infrastructure.

written from the facts on this page · September 2026

From the sources

Stalwart SMTP Server. Contribute to stalwartlabs/smtp-server development by creating an account on GitHub.

In the maker’s words, at launch

I am happy to announce Stalwart SMTP [1], a modern SMTP server developed in Rust with a focus on security, speed, and extensive configurability. It features built-in DMARC, DKIM, SPF and ARC support for message authentication, strong transport security through DANE, MTA-STS and SMTP TLS reporting, and offers great…

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