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Mohsen Azimi

tsz is a fast and eventually more sound TypeScript type checker.

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Rewrites the TypeScript type checker in Rust with native and WASM targets, aiming for tsc drop-in compatibility.

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dev tools

Description

tsz is a fast and eventually more sound TypeScript type checker. I read in the rules that existing projects do not qualify but I explicitly mentioned that I will be working on this for the hackathon when I signed up. I'm okay if this project is not accepted. It is still a work in progress so it was neither started or completed during this hackathon. But I would love to get more publicity and hopefully contributions to the project anyway. I've been working on this since Jan 1st!
tsz-org/tsz★ 57715 forksRustApache-2.0Created Jan 17, 2026 · last push Oct 21, 2026

README excerpt


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		<img src="crates/tsz-website/static/tsz_logo_light.png" alt="tsz logo" width="200">
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`tsz` is a performance-first TypeScript compiler in Rust. _z_ is for _Zang_!<sup>[1](#footnote-1)</sup>
The goal is a correct, fast, drop-in replacement for `tsc`, with both native and WASM targets.

`tsz` is built the with help of AI-assistant coding. Many tools and AI models were used during its development.

## Performance

`tsz` is aiming to be 2x faster than tsgo on all benchmarks. It is 3x faster in small file samples. Work on larger projects is underway.
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  <a href="https://tsz.dev/benchmarks/">
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      <source media="(prefers-color-scheme: dark)" srcset="crates/tsz-website/static/benchmark-data/readme-perf-dark.png">
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      <img src="crates/tsz-website/static/benchmark-data/readme-perf-light.png" alt="Latest tsz vs tsgo benchmark performance" width="760">
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## Install

> [!WARNING]
> `tsz` is pre-release software and not yet a drop-in replacement for `tsc`.
> Diagnostics, inference, and

Team