Microsoft Announces TypeScript 7.0 Beta

Microsoft has announced the TypeScript 7.0 Beta, representing a massive paradigm shift for the language. Over the past year, the TypeScript team has methodically ported the compiler codebase—previously bootstrapped and compiled to JavaScript—into Go.

10x Performance Gains

The move to Go is the headline feature of this release. By combining native code execution speed with shared memory parallelism, TypeScript 7.0 is roughly 10 times faster than TypeScript 6.0.

Parallelization: The compiler now parallelizes parsing, type-checking, and emitting.
Configurable Scaling: New flags like --checkers and --builders allow developers to fine-tune how the compiler utilizes multi-core systems, making it significantly faster for large monorepos.
Stable Semantics: Despite the language switch under the hood, the type-checking logic remains structurally identical to 6.0, ensuring full backward compatibility.

Getting Started

You can start testing the beta immediately. Because the package name typescript is reserved for the stable release, the beta is distributed under a different alias:

Installation: npm install -D @typescript/native-preview@beta
Execution: Run the new tsgo executable in place of tsc.
VS Code: Install the "TypeScript Native Preview" extension to experience the same performance gains directly in your editor.

Important Transition Notes

Side-by-Side Execution: To help teams transition, Microsoft has introduced a compatibility package, @typescript/typescript6, which exposes a tsc6 binary. This ensures you can run your existing 6.0 builds alongside your 7.0 testing without naming conflicts.
Hardened Defaults: TypeScript 7.0 adopts 6.0's strict defaults and hardens many previous warnings into errors. Notable changes include strict: true by default, module defaulting to esnext, and the removal of support for legacy targets like es5 and legacy module resolutions (e.g., amd, umd, systemjs).
JavaScript Support: The JavaScript analysis engine has been reworked for consistency with TypeScript's analysis, meaning some loosely typed JSDoc patterns that worked in previous versions may now require stricter adherence to TypeScript syntax.

What’s Next?

The team plans to ship the stable release of TypeScript 7.0 within the next two months. Upcoming work includes further optimizing the --watch mode, achieving parity on declaration file emit for JavaScript, and developing a stable programmatic API for the 7.1 release.

This release is a landmark achievement for developer tooling. By embracing Go, TypeScript is addressing the primary pain point of modern large-scale web development: build times. This provides a faster, more fluid experience when working on complex, multi-million-line codebases. You can find the full details and migration guide on the official TypeScript Blog.