TypeScript 7.0 RC Brings the Go-Native Compiler to the Main Package
Microsoft's from-scratch rewrite of the TypeScript compiler moves out of a preview package and into "npm install typescript@rc," promising roughly 10x faster type-checking.
Microsoft published "Announcing TypeScript 7.0 RC" on June 18, 2026, marking the point where its from-scratch rewrite of the TypeScript compiler — previously distributed as a separate preview package — becomes installable as the mainline typescript package itself, via npm install -D typescript@rc.
The rewrite, which the team originally previewed under the internal name Corsa and shipped experimentally as the tsgo binary, replaces the JavaScript-based compiler with one written in Go and compiled to native code. In the 7.0 RC, that native binary now runs directly as tsc — the separate tsgo name is retired for this release.
The headline number is performance: Microsoft describes TypeScript 7.0 as "often about 10x faster" than TypeScript 6.0, driven by native execution speed plus shared-memory parallelism that lets parsing, type-checking, and emit run concurrently instead of on a single thread. For large codebases where tsc time is a real part of the CI pipeline, that's a meaningful shift rather than an incremental tune-up.
Compatibility is handled deliberately rather than as an afterthought: a separate @typescript/typescript6 package ships a tsc6 binary, so teams can keep running the old JavaScript-based compiler side by side with the new one while they migrate — useful for anyone relying on tooling that hooks into the compiler's internals in ways the new native version doesn't yet support.
That caveat matters for the programmatic and plugin API specifically: it remains unstable in 7.0, with full API stability and broader ecosystem and editor-tooling support deferred to TypeScript 7.1, expected several months after 7.0 itself. Teams that just run tsc from the command line are in good shape; teams with custom tooling built on the compiler API should hold off migrating that tooling until 7.1.
Stable TypeScript 7.0 was targeted for mid-to-late July 2026, shortly after this RC. Full details, including migration notes for the API changes, are posted on Microsoft's TypeScript DevBlog.
Source: Microsoft TypeScript DevBlog — Announcing TypeScript 7.0 RC