Anthropic Rewrites Messages API in Rust Without Human Developers to Cut CPU Use 40% to 50%

Anthropic migrated its Messages API to the Rust programming language using its Claude AI model to generate source code from architectural plans created by human engineers, as the team lacked human Rust specialists. The transition reduced the API's CPU usage by 40% to 50% while maintaining performance parity with the previous version through testing against live traffic.