Anthropic ports Messages API from Python to Rust using Claude

Anthropic successfully migrated its Messages API from Python to Rust using a team with no prior Rust experience. By utilizing Claude to handle most of the implementation while engineers oversaw design and verification, the company achieved roughly 40 to 50 percent lower CPU usage and a 10 to 20 percent improvement in time to first token. The migration was conducted safely by running shadow traffic alongside the existing service before gradually shifting production traffic. Open article →