My Thoughts on Bun's Rust Rewrite

Sat, 16 May 2026 11:59:54 +0800

Before we discuss Rewrite Bun in Rust, there's something that needs to be said, because no one is saying it.

Bun stands where it does today because of Zig.

Jarred chose Zig back then not because it was "cool," but because Zig enabled a small team to rapidly prototype a high-performance JS runtime without a GC, without a heavy runtime. Zig's low friction, direct memory manipulation, and straightforward C interop were the core reasons Bun could punch above its weight on performance with an extremely small team in its early days. The architecture, data structures, and low-level design of Bun that you see today – that was shaped by Zig.

Bun on Jiacai Liu's personal website

My Thoughts on Bun's Rust Rewrite