“We are not forking TypeScript”: Cloudflare spearheads Rust port written by agents, for agents

Cloudflare is spearheading a new effort to bring Microsoft's TypeScript compiler to the Rust programming language, in an attempt to create a faster and more memory-efficient version. The company is not, however, forking TypeScript as some might think; rather, they are working closely with the TypeScript team to ensure that the new version, called tsrs, remains compatible.

Founder and Director of Engineering Christoph Nakazawa confirmed this on X, stating that tsrs is up to eight times faster and uses 70% less memory than TypeScript 7.0. The collaboration has already resulted in TypeScript 7.1 being 2.5 times faster than its predecessor. Cloudflare's decision to use Rust, as opposed to Microsoft's Go language for the TypeScript compiler, is driven by the language's compatibility with WebAssembly (Wasm) and its more direct control over memory, which can be advantageous in resource-constrained environments like browser-based development.

The project originated from Owner.com, where a 37,000-file TypeScript backend was causing performance issues. Head of AI developer experience Max Schwenk attempted to improve the Go compiler's memory usage but ultimately decided to let AI agents recreate the compiler in Rust, resulting in tsrs. This new version is planned to be integrated into Cloudflare's JavaScript ecosystem and developer tools.