Claude Code uses Bun written in Rust now
2 hours ago
- Jarred Sumner claimed Claude Code v2.1.181+ uses the Rust port of Bun, resulting in 10% faster startup on Linux.
- Evidence from strings command shows Bun v1.4.0 (a preview version) and 563 .rs source files embedded in Claude Code.
- The Rust version of Bun is now available as a canary release via `bun upgrade --canary`.
- A simple script can confirm the embedded Bun version by running `BUN_OPTIONS="--preload=/tmp/bun-version.ts" claude --version`.
- The commit updating Bun's version to 1.4.0 was made on May 17th, but hasn't been tagged in a stable release.