TypeScript 7 Release Candidate Arrives With Go-Based 10x Speed Boost
Microsoft's Go-based TypeScript 7 release candidate is here. See how the VS Code team migrated and the real-world speed gains from parallel compilation.
A year after Microsoft announced plans to rebuild TypeScript's compiler natively in Go, a release candidate is now available. It installs via npm and behaves like prior versions—type-checking code and compiling to ECMAScript-compatible output—while a native VS Code language server preview helps developers migrate existing projects.
The speed gains come from the Go-based compiler's ability to parallelize work through independent checker and builder workers, though tuning their count against available memory and CPU matters for large codebases and monorepos. TypeScript 6 serves as a bridge, sharing the same language changes as TypeScript 7, making it a practical stepping stone for testing migrations before committing fully.
The VS Code team's own migration offers a detailed case study: they used daily TypeScript 7 builds to catch issues early, kept TypeScript 6 as a fallback, and switched their bundler from webpack to esbuild for additional gains. The payoff was substantial—codebase-wide type checking became 7x faster, compile times dropped from 80 to about 20 seconds, and language server project loading fell from a minute to roughly 10 seconds.
While TypeScript 7.0 will be production-ready, its full programmatic API won't arrive until version 7.1. In the meantime, Microsoft's @typescript/typescript6 compatibility package and its tsc6 executable let teams run TypeScript 6 and 7 side by side, easing the transition without breaking existing build pipelines.