Cloudflare has unveiled tsrs, a port of the TypeScript compiler to the Rust programming language, built with JavaScript tooling company VoidZero and Max Schwenk of Owner.com. In a blog post on 20 October 2026, the company said: “We are doing this work in close collaboration with the TypeScript team, and incubating tsrs as part of the Oxc JavaScript compiler toolchain.”
The project is an experimental release on npm, and Cloudflare is keen to stress what it is not. “To be clear, we are not forking TypeScript,” it wrote. The aim is to make type-checking faster and lighter on memory, so developers wait less and full development environments can run in more places, including inside a web browser.
In brief
- Cloudflare, VoidZero and Max Schwenk of Owner.com have released tsrs, a Rust port of the TypeScript compiler, as an experimental npm package.
- Cloudflare says it is “not forking TypeScript” and is working “in close collaboration with the TypeScript team”, which stays in control of the language.
- In Cloudflare’s own early benchmarks, tsrs is up to 8x faster and uses about 70% less memory than TypeScript 7.0 with the same number of type-check workers.
A port, not a fork
TypeScript, created by Microsoft, adds types to JavaScript and is checked by a compiler before code runs. Cloudflare says the TypeScript team “should remain in full control of the language’s design and direction”. A Rust port has to follow the team’s decisions closely, “or it will eventually fall apart and become incompatible,” the post says.
That is why Cloudflare frames tsrs as a faithful port. “We have to preserve the TypeScript language strictly based on its original implementation – and the TypeScript team should remain solely responsible for deciding what that looks like,” it wrote. The company acknowledges there are still some differences from upstream TypeScript, such as the order in which diagnostics are printed, and says it aims to minimise them before a stable release.
What Cloudflare’s benchmarks show
“Early benchmarks of our Rust port of TypeScript are promising: tsrs is up to 8x faster and uses ~70% less memory compared to TypeScript 7.0 when using the same number of type check workers,” Cloudflare says. These are Cloudflare’s own figures.
The comparison also credits TypeScript’s own progress. The post says TypeScript 7.1 beta is “up to 2.5x faster than TypeScript 7.0”, adding: “Some of these optimizations were upstreamed from tsrs, and we’re hoping to find more.” Cloudflare says it worked with the TypeScript team to make sure the benchmarks compared the same configuration. By default, tsrs uses an adaptive set-up that uses more memory but runs faster still.
| Comparison with TypeScript 7.0 | Figure |
|---|---|
| tsrs speed (same type-check workers) | Up to 8x faster |
| tsrs memory | About 70% less |
| TypeScript 7.1 beta speed | Up to 2.5x faster |
Developers can try it with npm install tsrs and npx tsrs, Cloudflare says.
Why Rust, and why now
TypeScript’s own team has already ported the compiler from JavaScript to Go, which Cloudflare notes made it “10x faster and far more memory efficient”. Its case for Rust is WebAssembly. Compiling Go to WebAssembly means bundling Go’s garbage collector, the post explains, while Rust’s memory model suits running in WebAssembly hosts such as Cloudflare Workers, browsers and embedded devices.
That matters for AI agents, Cloudflare argues, because a small memory footprint lets whole development toolchains run in a sandbox. The company also says frontier AI models “can now do large-scale ports almost independently in a matter of days”, which explains the recent wave of TypeScript ports.
Keeping it in step
To stay compatible, Cloudflare plans to use the same agent-driven process it uses for Vinext, its Next.js-compatible project: agents review upstream changes daily and run the test suite nightly. It says it will try to contribute performance improvements back to TypeScript’s Go codebase. It is also working with Theo Browne to merge tsc-rs and tsrs into a single package that supports all of TypeScript’s features.
Our read
Cloudflare has gone out of its way to avoid looking like it is splitting TypeScript, and the fact that some tsrs optimisations have already been upstreamed supports that. The headline speed and memory gains are the company’s own early numbers on an experimental release. The real tests are whether independent benchmarks agree, and whether an agent-maintained port can stay faithful as TypeScript keeps evolving.
Sources
- Cloudflare: “Introducing tsrs: a Port of TypeScript to Rust” (Boshen Chen, Dimitri Mitropoulos and Christoph Nakazawa, 20 October 2026).
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