Cloudflare and VoidZero Introduce tsrs: An AI-Generated Rust Port of TypeScript

Cloudflare, working with VoidZero and Owner.com's Max Schwenk, announced tsrs, an AI-generated Rust port of the TypeScript compiler incubated in the Oxc toolchain, claiming up to 8x faster type checking and around 70% less memory than TypeScript 7.0 at the same number of checker workers. Schwenk said he wrote "zero" code, directing agents led by Claude Opus 5.5 to port the compiler using TypeScript's 15,197 conformance cases as the spec; on Owner's 37,000-file monolith a check that took 19 GiB and 80 seconds on TypeScript 7.0 dropped to 7 seconds. Independent testing measured smaller gains — 5.3x faster checking and 72% less memory in one benchmark, and 2.7x against the newer TypeScript 7.1 beta in another — while TypeScript's Daniel Rosenwasser noted much of the speed "does not just come down to language choice," and the release remains experimental with no watch mode or language server yet.

tsrs https://github.com/oxc-project/tsrs , a Rust port of the TypeScript compiler, has been announced by Cloudflare https://blog.cloudflare.com/typescript-rust-port/ , which is developing it with VoidZero and Max Schwenk of Owner.com http://Owner.com , incubating the project inside the Oxc toolchain https://github.com/oxc-project and working in close collaboration with the TypeScript team. Cloudflare is emphatic that this is not a fork, with the TypeScript team retaining full control over the language's design. Cloudflare's benchmark https://blog.cloudflare.com/typescript-rust-port/ comparing tsrs against TypeScript 7.0 at the same number of checker workers The headline numbers are a claimed up to 8x faster type checking and around 70% less memory https://blog.cloudflare.com/typescript-rust-port/ than TypeScript 7.0 at the same number of checker workers. Rust also unlocks the use case of compiling to WebAssembly through @tsrs/wasm https://www.npmjs.com/package/@tsrs/wasm so checks can run in a browser or on Workers, without dragging a garbage collector into the bundle the way a Go binary does. To try, developers simply point it at an existing tsconfig and run: npm install -D tsrs npx tsrs -p . --noEmit In a detailed write-up https://building.owner.com/tsrs , Schwenk explains he wrote "zero" code, instead directing agents led by Claude Opus 5.5 to produce a faithful port, using TypeScript's own 15,197 conformance cases as the spec. On Owner's 37,000-file monolith, a check that needed 19 GiB and 80 seconds on TypeScript 7.0 dropped to 7 seconds. One developer benchmarked both npm packages https://dev.to/frankchu/cloudflare-says-its-rust-typescript-port-is-8x-faster-i-measured-53x-and-72-less-memory-1fdm and measured 5.3x faster checking and 72% less memory, with identical diagnostics and byte-identical emit, but spotted that tsrs exits with code 2 on type errors where tsc exits 1, enough to quietly break a CI script. Measuring against the newer TypeScript 7.1 beta https://devblogs.microsoft.com/typescript/announcing-typescript-7-1-beta/ rather than 7.0, ImportStatic found https://importstatic.com/rust/tsrs-vs-tsgo-typescript-7-1 a smaller 2.7x gain, a reminder that the 8x headline is measured against the older baseline. TypeScript's Daniel Rosenwasser responded https://news.ycombinator.com/item?id=50167925 that much of the speed "does not just come down to language choice," and that some optimisations discovered in tsrs are feeding into a leaner TypeScript 7.1. Peter Steinberger reported https://x.com/steipete/status/2112571535731106013 on X: Moved to tsrs over the weekend. Drop-in replacement. Around 5x faster for OC. Kind of amazing that it took Microsoft a team and two years to rewrite the TS compiler in go, and now you can just let an agent rip and get sth significantly better within weeks. Others were wary, questioning https://news.ycombinator.com/item?id=50168234 whether the arena-based, never-freed memory model is sound. tsrs sits alongside Microsoft's own Go-based compiler, known as tsgo, and Theo Browne's rival Rust port, tsc-rs . Rather than compete, Cloudflare is merging https://daily.dev/posts/tsrs-ships-and-theo-s-rival-port-just-got-absorbed-wxzirxmz4 tsc-rs and tsrs into a single package, adding language server and content mapper support. The release remains experimental. There is no watch mode or language server yet, --init and --showConfig are unsupported, and diagnostic order can differ, the compatibility notes https://github.com/oxc-project/tsrs/blob/main/docs/COMPATIBILITY.md provide more details. Because tsrs tracks TypeScript 7, teams still on TypeScript 5 or 6 should first adopt Microsoft's native Go port https://devblogs.microsoft.com/typescript/typescript-native-port/ before swapping in tsrs, after which migrating is as simple as reusing the existing tsconfig. tsrs is open source under Apache-2.0 and available on GitHub https://github.com/oxc-project/tsrs .