Bun has transitioned to Rust with over a million lines of code and 6,755 commits, primarily generated by Claude Code agents in nine days. The previous Zig implementation has been removed following Anthropic's acquisition of Bun in December.

Bun is a software that enhances the experience of working with TypeScript by providing speed and practicality for scripts, apps, tests, and tooling. Anthropic has acquired Bun, raising concerns about its future as a serious alternative to Node.js.

Bun has achieved a 100x speed increase by rewriting Git in the Zig programming language and integrating it into its runtime. This enhancement significantly improves performance for developers using Bun.