Stalwart 1.0 Open-Source Mail Server Hits First Stable Release

After five years of development, the Rust-based open-source mail server Stalwart has reached version 1.0, its first stable release. Rewritten SIMD and SWAR parsers let it handle 5,445 inbound SMTP messages per second versus Postfix's 723, and full-text search over 250,000 messages takes under 4 ms.

• Stalwart handled 5,445 SMTP messages/s versus 723 for Postfix
• Won 35 of 38 benchmarks against Postfix 3.11 and Dovecot 2.4
• Full-text search over 250,000 messages takes under 4 ms
• Adds post-quantum DKIM2 signatures using ML-DSA-44 and Ed25519