● Covered by 3 sources · 4 reportsMedium impact4 neutral
TypeScript Compiler, Checker, and LSP Ported to Rust Using LLMs
Key points
- TypeScript compiler, checker, and LSP ported to Rust.
- LLMs, primarily Claude Opus 5.5, performed the porting.
- Achieved 100% compatibility in tested real-world projects.
- Provides a drop-in replacement for most TypeScript apps.
- Cloudflare, VoidZero, and Owner.com are developing tsrs.
- tsrs is incubated as part of the Oxc JavaScript compiler toolchain.
- tsrs is up to 8x faster and uses 70% less memory than TypeScript 7.0.
- Cloudflare's director of engineering Christoph Nakazawa confirmed the company is taking ownership of tsrs.
- TypeScript 7.1 is already ~2.5x faster due to shared optimizations.
- Max Schwenk of Owner.com helped develop tsrs.
- tsrs can compile to WebAssembly via @tsrs/wasm.
- Cloudflare states tsrs is not a fork; TypeScript team retains full control.
- Max Schwenk wrote zero code, directing AI agents to produce the port.
- TypeScript's 15,197 conformance cases were used as the specification.
- Owner.com's 37,000-file monolith was used for testing.
LLM-Assisted Porting to Rust
A new project has successfully ported the TypeScript compiler, checker, and language server protocol (LSP) to Rust. This port, named tsc-rs, was primarily accomplished using large language models (LLMs). Initial attempts with OpenAI's GPT-5.6 Sol and GPT 6 Astra models incurred over $400,000 in token costs and did not achieve full compatibility. However, Claude Opus 5.5 completed a working version in 10 hours, starting from scratch, with a total token spend of approximately $24,047 over two weeks.
Project Goals and Compatibility
The project aimed to test LLM capabilities, create a fast TypeScript type checker, and enable high-performance TypeScript checking in WebAssembly (WASM). The tsc-rs port claims 100% compatibility in all tested real-world projects and functions as a drop-in replacement for the majority of applications. It maintains the algorithms and behavior of the original TypeScript compiler, which is written in Go, and uses the same command-line interface (tsc), language server, and API.
Installation and Usage
Users can install tsc-rs via npm using `npm install -D tsc-rs` and execute it with `npx tsc-rs -p tsconfig.json`. The `tsc-rs` command accepts the same options as the standard `tsc` command. The npm package is named `tsc-rs` to avoid conflicts with the existing `typescript` package. Standalone archives containing the `tsc` binary and lib files are also available for Linux x64 and macOS arm64 platforms.
Integrated Language Service Diagnostics
tsc-rs includes built-in Effect language service diagnostics (codes 377xxx). This integration means that Effect projects do not require a separate compiler, as these diagnostics originate from the same check as TypeScript diagnostics and are displayed by the language server.
Updates
- Max Schwenk of Owner.com helped develop tsrs.
- tsrs can compile to WebAssembly via @tsrs/wasm.
- Cloudflare states tsrs is not a fork; TypeScript team retains full control.
- Max Schwenk wrote zero code, directing AI agents to produce the port.
- TypeScript's 15,197 conformance cases were used as the specification.
- Owner.com's 37,000-file monolith was used for testing.
- Cloudflare, VoidZero, and Owner.com are developing tsrs.
- tsrs is incubated as part of the Oxc JavaScript compiler toolchain.
- tsrs is up to 8x faster and uses 70% less memory than TypeScript 7.0.
- Cloudflare's director of engineering Christoph Nakazawa confirmed the company is taking ownership of tsrs.
- TypeScript 7.1 is already ~2.5x faster due to shared optimizations.
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Primary sources
GitHub cmc_internal/api GitHub github/collect GitHub pingdotgg/ts-rust GitHub _private/browser GitHub get-started/accessibility GitHub open-source/sponsorsHow outlets covered it
Cloudflare and VoidZero, with Max Schwenk, released tsrs, a Rust port of the TypeScript compiler, developed using AI agents. tsrs offers up to 8x faster type checking and 70% less memory usage compared to TypeScript 7.0, and can compile to WebAssembly.
Cloudflare has taken ownership of tsrs, a Rust port of the TypeScript compiler, which it claims is up to eight times faster and uses 70% less memory than TypeScript 7.0. This initiative aims to reduce computing resource consumption for AI coding agents checking their work, with Cloudflare collaborating with Microsoft's TypeScript team to share optimizations.
Cloudflare, VoidZero, and Owner.com are developing tsrs, a Rust port of the TypeScript compiler, in collaboration with the TypeScript team. This project aims to improve TypeScript's performance and memory efficiency, with early benchmarks showing tsrs is up to 8x faster and uses 70% less memory than TypeScript 7.0.
A new project, tsc-rs, has successfully ported the TypeScript compiler, checker, and language server protocol (LSP) to Rust. This port was achieved using large language models (LLMs), specifically Claude Opus 5.5, and aims to provide a faster TypeScript type checker with high performance, including in WebAssembly environments.