ts-r

Fast TypeScript tooling, written from scratch in Rust. ts-r type-checks, lints, bundles, runs and serves TypeScript with the same results as the tools you use today, and faster: ts-r-check type-checks the benchmark repos 2–7× faster than tsc 7 (benchmarks). Each tool is its own small binary and works on its own next to tsc, ESLint and Vite, so you can adopt one without the rest.

npm install --save-dev @ts-r.dev/cli@next   # the ts-r launcher and every tool
npx ts-r check           # type check, with tsc 7's diagnostics
npx ts-r lint            # lint, with ESLint and typescript-eslint rules
npx ts-r build           # bundle, with esbuild's CLI
npx ts-r run server.ts   # run TypeScript (replaces tsx / ts-node)
npx ts-r dev             # dev server with HMR and Vite's import.meta.hot

Status: preview. The type checker is the most mature tool. It gives tsc 7's exact output on 87% of TypeScript's own conformance tests. It also matches tsc 7 exactly on typeorm, playwright, tRPC, date-fns and the React compiler. Every other tool works on real projects but has known gaps (below). Version numbers stay below 1.0 until that changes.

Contents

• The tools
• Install
• Benchmarks
• How it works
• Build from source
• Contributing
• Sponsors
• License

The tools

Tool	Replaces	Works today	Known gaps
ts-r-check	tsc (type checking, emit, --build, --watch)	tsc 7's codes, messages and chains; JavaScript, declaration and source-map emit; project references	Some inference and JSX typing; 13% of conformance tests still differ
ts-r-lint	ESLint, oxlint	103 rules that pass every case of ESLint's and typescript-eslint's own tests; flat config, oxlint and Biome configs	No type-aware rules; plugins other than typescript-eslint
ts-r-build	esbuild, vite build	esbuild's CLI flags; ESM, CJS and IIFE output; code splitting; minification; source maps; --watch	No plugins, no CSS bundling, no lowering below ES2022
ts-r-run	tsx, ts-node	Runs TypeScript on Node 22.15+ with tsc 7's JavaScript output	Only the entry's tsconfig is used
ts-r-dev	vite dev	Hot reload, Vite's import.meta.hot API, React Fast Refresh, dependency pre-bundling	No vite.config, no HTTPS
ts-r-lsp	tsserver, the ESLint server	One server per workspace for lint and types; our checker or your own TypeScript as the type backend	Most projects still fall back to tsserver for diagnostics
ts-r		Launcher for all of the above, plus ts-r ci (check, lint and build in parallel) and ts-r doctor

What each tool matches, and how it is measured: each crate's AGENTS.md and the design records in docs/design/.

Install

Every tool is an npm package with a native binary for macOS (arm64, x64), Linux (arm64, x64; glibc and musl) and Windows (arm64, x64). Install one, or the ts-r launcher (@ts-r.dev/cli) with all of them:

npm install --save-dev @ts-r.dev/cli@next      # every tool and the ts-r launcher
npm install --save-dev @ts-r.dev/check@next    # just ts-r-check (or run, dev, build, lint, lsp)

To type-check with ts-r wherever your scripts and tools already run tsc, use the drop-in typescript package. It runs ts-r-check where ts-r-check gives the same result as your own TypeScript on that project, and hands everything else to your TypeScript:

// package.json
"devDependencies": {
  "typescript": "npm:@ts-r.dev/typescript@^7",
  "typescript-real": "npm:typescript@^7.0.0"
}

The details are in npm/typescript/README.md. Packages and platforms are in npm/ts-r/README.md.

Benchmarks

Each table shows ts-r's median time per scenario next to the fastest other tool on the same workload. Workloads include type-checking pinned open-source repos (tRPC, date-fns, rxjs) and bundling three.js ten times over, among others. Every pull request is benchmarked against its base on dedicated cores, and a slowdown beyond the gate blocks the merge. Method and scenarios: bench/README.md.

Unreleased (main)

Benchmark	ts-r	Fastest other tool	ts-r is
version-startup	ts-r 1.73 ms	esbuild 4.64 ms	2.7× faster
check-trpc	ts-r-check 410 ms	tsc-7 969 ms	2.4× faster
check-date-fns	ts-r-check 889 ms	tsc-7 1.76 s	2.0× faster
check-rxjs	ts-r-check 980 ms	tsc-7 6.53 s	6.7× faster
build-three-x10	ts-r-build 1.28 s	esbuild 1.21 s	1.1× slower

Medians on linux-x86_64 (four dedicated cores), measured 2026-10-21. Scenarios: bench/scenarios.toml and bench/repos.toml.

The table above is updated by every sync to main. The one below is the same table at the time of the latest release, and is updated by each release pull request.

Latest release

Release v0.1.0-alpha.2:

Benchmark	ts-r	Fastest other tool	ts-r is
version-startup	ts-r 1.73 ms	esbuild 4.64 ms	2.7× faster
check-trpc	ts-r-check 410 ms	tsc-7 969 ms	2.4× faster
check-date-fns	ts-r-check 889 ms	tsc-7 1.76 s	2.0× faster
check-rxjs	ts-r-check 980 ms	tsc-7 6.53 s	6.7× faster
build-three-x10	ts-r-build 1.28 s	esbuild 1.21 s	1.1× slower

Medians on linux-x86_64 (four dedicated cores), measured 2026-10-21. Scenarios: bench/scenarios.toml and bench/repos.toml.

How it works

Every layer is written in this repo, with no other compiler, bundler or linter underneath: lexer, parser, binder, type checker, transformer, code generator, minifier, module resolver, bundler, linter, dev server and language server. TypeScript's, esbuild's and ESLint's test suites and outputs are the oracles: ts-r runs them and compares, and does not copy their code.

Path	What it is
crates/ts_r_lexer, ts_r_parser, ts_r_ast	Error-recovering parser for TS, TSX and JS into a compact, index-based AST
crates/ts_r_binder, ts_r_checker	Scopes and symbols; the type checker
crates/ts_r_transform, ts_r_codegen, ts_r_emit	TypeScript to JavaScript, printing, source maps and declaration files
crates/ts_r_resolver, ts_r_config	Node and TypeScript module resolution; tsconfig.json
crates/ts_r_bundler, ts_r_minify	The bundler and minifier behind ts-r-build and ts-r-dev
crates/ts_r_lint	Lint rules and config loading
crates/ts_r_lsp, editors/vscode	Language server and the VS Code extension
docs/design/	Design records: why each piece works the way it does

AGENTS.md has the full crate map and the rules every change follows.

Build from source

You need the Rust toolchain pinned in rust-toolchain.toml (rustup installs it) and Node 22 or newer for the tests that compare against tsc and esbuild.

git clone https://github.com/Webb-Ventures/typescript-rust
cd typescript-rust
cargo xtask upstream sync --minimal   # TypeScript's lib files, which the checker tests need
cargo build --release                 # binaries in target/release
cargo test --workspace

cargo xtask also runs the oracles (cargo xtask oracle), the benchmarks (cargo xtask bench) and the top-npm-packages harness (cargo xtask ecosystem). See xtask/AGENTS.md.

Contributing

Contributions are welcome: bug reports, mismatches with tsc or ESLint, and pull requests.

• CONTRIBUTING.md: how to set up, the checks a change must pass, and how pull requests are reviewed and merged.
• AI_POLICY.md: AI-assisted work is welcome from Anthropic's, OpenAI's and Meta's Muse models only. Pull requests that credit any other model are closed automatically.
• CODE_OF_CONDUCT.md and SECURITY.md (report vulnerabilities privately).
• CHANGELOG.md: what changed in each release.

Sponsors

ts-r is free and open source, and its development is funded by sponsors.

Webb Ventures Founding sponsor

Sponsor ts-r: if ts-r saves your team time, support its development. Sponsors are listed here.

License

ts-r is dual-licensed under either of

• the MIT license (LICENSE-MIT), or
• the Apache License, Version 2.0 (LICENSE-APACHE),

at your option. Unless you say otherwise, any contribution you submit for inclusion in ts-r is dual-licensed as above, with no additional terms or conditions.

TypeScript's lib files shipped with ts-r-check and ts-r-lsp are under TypeScript's own Apache-2.0 license, included next to them. Upstream test data fetched by cargo xtask upstream sync stays in the gitignored target/ directory under its own license.