On June 18, 2026, Microsoft released the Release Candidate of TypeScript 7.0 — and this isn’t just another incremental update. It’s a complete rewrite of the compiler in Go, delivering up to 10× faster compilation compared to TypeScript 6.0. If you work with large TypeScript codebases, this is the news you’ve been waiting for.
Why the Switch to Go?
TypeScript has always been a bootstrapped language — the compiler was written in TypeScript and compiled to JavaScript. This imposed fundamental performance limitations. Microsoft chose to port to Go not to promote Go as a language, but because the combination of native code speed and shared memory parallelism delivers dramatic results. The team spent over a year methodically porting the existing implementation — not rewriting from scratch — meaning the type-checking logic remains structurally identical to TypeScript 6.0.
What Does TypeScript 7.0 RC Actually Bring?
The performance leap is the most visible benefit. Building VS Code, which previously took 77 seconds, now takes just 7. Type checking is 30× faster. Memory usage is 2.9× lower. But there’s much more:
- Parallel type checking: TypeScript 7.0 creates a fixed number of type-checker workers (default is 4, configurable via the
--checkersflag), ensuring consistent results while delivering significant speedups. - Parallel project reference building: The new
--buildersflag enables parallel builds in monorepos — ideal for teams working with dozens of interdependent packages. - Rebuilt watch mode: Built on Parcel’s file-watcher (ported to Go), it provides stable and efficient cross-platform file watching without relying on polling.
- Side-by-side TypeScript 6.0 support: A new compatibility package
@typescript/typescript6with atsc6binary lets you run both versions simultaneously.
New Defaults and Breaking Changes
TypeScript 7.0 adopts TypeScript 6.0’s defaults and adds hard errors for deprecated flags. Key changes: strict is now true by default, module defaults to esnext, types defaults to [] (empty array). Support for target: es5, moduleResolution: node/node10, and AMD, UMD, SystemJS modules has been removed.
One interesting addition is proper Unicode code point handling in template literal types — emoji like 😀 are now correctly treated as single characters rather than two UTF-16 surrogates.
How to Try TypeScript 7.0 RC
Installation is straightforward:
npm install -D typescript@rcFor VS Code, the TypeScript Native Preview extension lets you use the new compiler in the editor immediately. The stable TypeScript 7.0 GA release is planned approximately one month after the RC — around mid-July 2026. Now is the perfect time to test the RC on your projects and provide feedback to the Microsoft team.
Conclusion
TypeScript 7.0 RC represents one of the most significant technological leaps in TypeScript’s history. 10× faster compilation, dramatically lower memory usage, and new parallelization capabilities are compelling reasons to test the RC as soon as possible. Download it, run it against your codebase, and share your results — the community is listening.
