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Stalwart Blog

Stalwart Keep: The Fastest Way to Run a Mail Cluster

A mail cluster spends its day asking small questions: is this message locked, has this client hit its limit, did anything change? Stalwart Keep is the server we built to answer them. It replaces Redis and a message broker with one service, finishes 99% of requests within 59 microseconds at a large deployment’s typical load, and has been through Jepsen.

Stalwart v1.0: The Fastest Mail Server on the Planet

Five years ago, on 3 October 2021, the first commit landed in a small repository called mail-parser. That e-mail parsing library became the seed of a complete mail and collaboration server, and today, after five years of continuous development, we are proud to announce Stalwart v1.0, the first stable release.

Version 1.0 is about two things: speed and stability. We spent months profiling, benchmarking and rewriting the hot paths of the server, and the result is a mail server that outperforms the Postfix and Dovecot combination in 35 of 38 head-to-head benchmarks. We also finalised the database schema, so future releases will no longer require disruptive migrations.

Private Tests, Public Code: Protecting Stalwart from AI Clones

Open source works because it is a relationship that benefits both sides. Lately, a few actors have started treating Stalwart as something to feed on instead. This post explains what has been happening, why our test suites are moving to a private repository, why the license is not changing, and how the Enterprise edition keeps the Community edition alive.