Stalwart Keep: The Fastest Way to Run a Mail Cluster

· Stalwart Labs Ltd. · Nov. 9, 2026, 11:14 a.m.
Summary
This blog post introduces Stalwart Keep, a new in-memory store and coordinator designed for high-performance mail clusters. Built in Rust, it minimizes latencies by ensuring that requests are handled efficiently through a share-nothing architecture. The post details its features, architecture, and performance benchmarks compared to other systems like Redis and Valkey, showcasing Keep's ability to serve high loads with less resource consumption and achieving low latency responses.