Bun is a modern JavaScript runtime like Node or Deno. It was built from scratch to focus on three main things:

Start fast (it has the edge in mind).

New levels of performance (extending JavaScriptCore, the engine).

Being a great and complete tool (bundler, transpiler, package manager).

[…]

The goal of Bun is to run most of the world’s JavaScript outside of browsers, bringing performance and complexity enhancements to your future infrastructure, as well as developer productivity through better, simpler tooling.

Bun looks interesting so far, not sure we needed another runtime but it seems pretty fast, and I'm sure we'll hear more about it.