Dev Tools · 1h ago
Why Anthropic's Claude Code Runs on Bun Over Node.js
Anthropic's Claude Code CLI uses Bun instead of Node.js for faster startup and simpler distribution. Bun's 5-15ms cold start beats Node's 50-80ms, crucial for a CLI invoked frequently. The runtime also bundles TypeScript into a single binary, eliminating Node.js dependency.
Meridian48 take
The choice highlights Bun's growing maturity for developer tooling, but the opaque lockfile and native module risks mean it's not a universal Node replacement yet.
claude-codebun-runtime