Cloudflare introduces tsrs, an experimental Rust port of TypeScript

Experimental release, not a new language direction

Cloudflare says it is developing tsrs, a Rust port of the TypeScript compiler, with VoidZero and Max Schwenk of Owner.com. The project is being incubated within the Oxc toolchain in collaboration with the TypeScript team, according to the Cloudflare announcement.

The stated goal is to preserve TypeScript’s upstream language behavior, not establish a separate language direction. Cloudflare describes an experimental npm release that developers can install with npm install tsrs and run with npx tsrs. A stable release remains a future milestone, according to the announcement.

Performance claims depend on the comparison

Cloudflare reports early benchmarks showing tsrs running up to 8× faster and using approximately 70% less memory than TypeScript 7.0 with the same number of type-check workers. These are vendor-reported results, not a guarantee for other workloads. Source: Cloudflare.

The announcement also reports TypeScript 7.1 beta running up to 2.5× faster than 7.0 and says some optimizations were upstreamed from tsrs. That moving baseline matters: engineers should compare tsrs against the compiler version they actually use rather than assume the headline advantage applies equally to newer releases.

Cloudflare also says tsrs defaults to a machine-dependent adaptive configuration that uses more memory for additional speed. The matched-worker results should therefore not be treated as default-to-default results. Compiler versions, worker settings and hardware are necessary context for evaluating the headline numbers.

Compatibility remains an evaluation priority

Cloudflare says it is working with Theo Browne to merge tsc-rs and tsrs into a single package intended to support all TypeScript features. That is planned scope, not confirmation of complete coverage in the experimental release. The announcement acknowledges existing differences from upstream TypeScript, including the order in which diagnostics are printed. Source: Cloudflare’s compatibility plans.

Cloudflare cites WebAssembly portability and memory efficiency as reasons for choosing Rust. Those motivations should not be confused with a guarantee that the experimental compiler is ready for production or equivalent to upstream TypeScript in every environment.

For teams evaluating tsrs, a practical first step is to keep the existing compiler as the build gate and run tsrs alongside it. Compare diagnostics, exit status, elapsed time and peak memory on the same code and hardware, recording compiler versions and worker settings. The useful question is whether a speedup survives your configuration without changing the results your build relies on.