Vercel Labs' Tsc-ts Ports TypeScript 7.0.2 Back Into TypeScript, With No Timings Published

Vercel Labs has published tsc-ts, an experimental port of the TypeScript 7.0.2 compiler written in TypeScript, then compiled to a native executable by a second Vercel Labs tool, scriptc. The README claims output parity with Microsoft's Go-based build and publishes no timing.

That omission matters because speed was the whole argument for the original. Microsoft announced TypeScript 7 on July 8, 2026 as "a 10x faster native port of TypeScript," built in Go. The tsc-ts README mentions an npm run bench script that compares against tsgo, the Go build's preview name, and against the JavaScript compiler. It shows no results.

The repository shows 263 stars, 4 forks, 618 commits and one open issue. It carries a Vercel Labs experiment badge and names no individual maintainers. The Terminal has not built or run it.

What the parity claim covers

The README says the project is "ported from tsgo 7.0.2 as idiomatic TypeScript," with tsgo as the correctness oracle. For each stage it reports "all match" against the reference: scanner, parser, binder, module resolution, tsconfig handling, command line, diagnostics catalog, emit for 39 option sets, declaration emit, --build and --incremental, and the type checker's per-file diagnostics.

The corpus is TypeScript's own test suite: about 12,500 files, or about 17,000 units once multi-file cases are split. The editor-facing --api server is checked response by response against tsc --api 7.0.2.

	TypeScript 7.0 (Microsoft)	tsc-ts (Vercel Labs)
Written in	Go	TypeScript, compiled by scriptc
Speed claim	10x faster, in Microsoft's words	None published
Stage	Announced July 8, 2026	Labelled experimental
Test oracle	Not given in the post excerpt	tsgo 7.0.2 output

What it takes to build, and what fails

The build is not casual. The README asks for Node.js 24 or later, Go 1.26 for the reference builds, clang for linking and a scriptc host on macOS, Linux or Windows. It pins scriptc 0.3.5 and fails with any other version. Users install the finished compiler from npm and run npx tsc-ts -p tsconfig.json, which pulls a per-platform binary such as @tsc-ts/linux-x64-gnu.

Two gaps are listed. Completions that need auto imports, covering global identifiers, import statements and exhaustive switch cases, return the error "completion list needs auto imports." The profiling methods startCPUProfile, stopCPUProfile and saveHeapProfile are unsupported.

The tool underneath is also experimental

The scriptc repository, 6.2k stars, describes itself as a TypeScript-to-native compiler that "uses the types checked by the TypeScript compiler to generate machine code." Its README calls it experimental and says it "supports a subset of JavaScript, TypeScript, and Node.js APIs." The scriptc site lists no version, licence or benchmark on its front page. The scriptc repository has a benchmarks directory with no results shown on the page.

Both projects are Apache-2.0 licensed. So tsc-ts doubles as a test of scriptc: if the native build of a compiler produces the same diagnostics as tsgo, every "all match" line also says something about the tool that compiled it.

Readers deciding whether any of this matters for a build pipeline have one concrete step. Microsoft's 10x figure describes TypeScript 7 on the Go build; nothing fetched here says tsc-ts is faster or slower than that. The Orca coverage made the same point about stars, and the Iroh 1.0 report about a figure with no named origin: a project's headline number is only as good as the page it links. Until the README's benchmark script has output, the only measured claim is parity.