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

Oct 26, 2026 - 16 min read

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.

Marginal Gains: Major Impact

Dec 16, 2025 - 5 min read

Mauro D.

Project Maintainer

In professional cycling, the concept of marginal gains became famous through Team Sky. Rather than chasing dramatic breakthroughs, they focused on making hundreds of small improvements: slightly better bike fit, marginally lighter components, improved sleep, cleaner nutrition. None of these changes mattered much on their own, but together they reshaped performance—and helped dominate the sport for years.

Software systems, especially large distributed ones, work much the same way. Rarely does a single feature transform everything overnight. More often, real progress comes from careful attention to small details: shaving latency here, reducing contention there, simplifying a hot path, rethinking a data structure.

Stalwart v0.15 is very much a release in this spirit. It does not introduce a long list of headline features. Instead, it is the result of revisiting core subsystems—spam filtering, search, storage, and data access—and making many targeted improvements that, together, have a significant impact on performance, reliability, and usability.