Theo (T3) open-sourced ts-rust (npm: tsc-rs), a Rust port of Microsoft's Go-native TypeScript compiler, checker and language server. Months of GPT-5.6 Sol / GPT 6 Astra runs cost over $400K in API-priced tokens and stalled near 84% compatibility; Claude Opus 5.5 restarted from scratch, reached a working v0 in 10 hours and finished in two weeks for about $24,047. All 181,711 ported Go tests pass, it type-checks 1.61x faster than tsc 7 (geometric mean over six open-source apps), ships Effect diagnostics built in and has a WASM build.

Key Takeaways

  • ✓Cost: GPT-5.6 Sol / GPT 6 Astra burned $400K+ and stalled near 84% compat; Opus 5.5 finished in 2 weeks for ~$24,047 (README)
  • ✓Correctness: all 181,711 ported Go tests pass; TanStack Query core and Hono diagnostics match Go exactly
  • ✓Speed: geometric mean 11.4x over tsc 6 and 1.61x over tsc 7 on six apps; VS Code (3.75M lines) 4.20s vs 6.84s for tsc 7; bun check is still fastest (20.9x)
  • ✓T3 Code: 7.25s vs 16.10s for tsc 7 without Effect (2.22x); 11.13s vs 21.07s with Effect diagnostics (1.89x)
  • ✓Early release: Linux x64 and macOS arm64 only; known monorepo TS6059 and tsc -b stale-output issues
Theo open-sources tsc-rs: Opus 5.5 ported the TypeScript 7 compiler to Rust in two weeks for ~$24K, type-checking ~1.6x faster than the Go version
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Key Decision Metrics at a Glance

TL;DR Verdict
🏆 Benchmark RankRank
Cost: GPT-5.6 Sol / GPT 6 Astra burned $400K+ and stalled near 84% compat; Opus 5.5 finished in 2 weeks for $24,047 (README)
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Project Links & Resources

Direct Access
Direct access to official project resources and documentation
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pingdotgg/ts-rust (GitHub)
github.com/pingdotgg/ts-rust
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ts-rust v0.1.0 release
github.com/pingdotgg/ts-rust/releases
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tsc-rs on npm
www.npmjs.com/package/tsc-rs
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microsoft/TypeScript (Go native compiler)
github.com/microsoft/TypeScript
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Effect-TS/tsgo
github.com/Effect-TS/tsgo
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In-Depth Technical Analysis

Theo (T3) open-sourced ts-rust / tsc-rs, an MIT-licensed Rust port of Microsoft's Go-native TypeScript compiler, type checker and LSP, pinned to TypeScript 7.1.0-dev revision 673a5f17d713. Per the README, months of GPT-5.6 Sol and GPT 6 Astra /goal loops produced 1.3M lines of Rust and over $400K of API-priced tokens but never passed ~84% compatibility; Claude Opus 5.5 started from scratch, had a working v0 in 10 hours and finished in about two weeks for ~$24,047 (925-983% of a $200 plan's weekly limits). All 181,711 ported Go tests pass. In the author's own hyperfine runs on an M4 Pro, tsc-rs is 11.4x faster than tsc 6 and 1.61x faster than tsc 7 (geometric mean over six apps); bun check remains fastest at 20.9x but lacks Effect diagnostics, which tsc-rs builds in. Install with npm install -D tsc-rs and run npx tsc-rs -p tsconfig.json; only Linux x64 and macOS arm64 are supported, and known issues include TS6059 in some monorepos and stale outputs in tsc -b without project references. Theo says four of the first five filed issues reproduced upstream TypeScript behavior.

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