Anthropic Rewrites Messages API in Rust with Claude, Cutting CPU 40-50%

Anthropic rewrote its core Messages API in Rust entirely with code written by Claude, despite having no Rust engineers on the team. Humans wrote the plans and validated behavior against real traffic, achieving a 40-50% reduction in CPU usage.

2026-10-31 ~ 2026-10-31 · 2 related posts

• Anthropic rewrote its Messages API in Rust with zero Rust devs — Claude wrote the code, CPU down 40-50% — matt_slotnick · 2026-10-31
• Anthropic Rewrote Its Messages API in Rust With Zero Rust Devs, CPU Down 40-50% — kieranklaassen · 2026-10-31