Cloudflare and VoidZero start tsrs, a Rust port of TypeScript, under Oxc
Victoria Shinder2 min readCloudflare and VoidZero, working with Max Schwenk of Owner.com, have announced tsrs, a Rust port of the TypeScript compiler incubated in the Oxc JavaScript toolchain. Cloudflare says the work is done in close collaboration with the TypeScript team and stresses that it is not a fork: the TypeScript team remains in control of the language's design, and the port has to follow its decisions to stay compatible.
Cloudflare's early benchmarks put tsrs at up to 8x faster than TypeScript 7.0 with about 70% less memory when both use the same number of type-check workers, a configuration it says was agreed with the TypeScript team. It notes that TypeScript 7.1 beta is itself up to 2.5x faster than 7.0, and that some of those optimisations were upstreamed from tsrs. An experimental package is on npm. Known differences remain, such as the order in which diagnostics are printed.
The stated reason for Rust, given that the Go port already made TypeScript about 10x faster, is WebAssembly: a Go program compiled to Wasm carries its garbage collector, while Rust's memory model keeps the module small. Cloudflare wants to run complete development toolchains inside Workers and in the browser. The post also says frontier AI models can now do large ports almost independently, and that tsrs will be kept in sync with upstream by agents that review changes daily and regenerate a compatibility matrix nightly, as Cloudflare does for its Vinext port of Next.js. It plans to merge tsrs with Theo Browne's tsc-rs.
What it means
The speed numbers are the headline, but the strategic point is placement: a type checker that fits in Wasm can run where a Go binary cannot. The open question is maintenance. A port that depends on agents to track every upstream change is a bet that this process stays reliable as TypeScript evolves, and diverging diagnostics are the first place users will notice if it does not.