TypeScript History & Versions

How TypeScript started

By 2010, teams at Microsoft were building very large applications in JavaScript, such as the web version of Office, and found that a dynamically typed language made big codebases hard to refactor and navigate. A team led by Anders Hejlsberg, who had earlier designed Turbo Pascal, Delphi and C#, set out to add optional static types to JavaScript without changing how JavaScript runs.

TypeScript was announced on 1 October 2012 (version 0.8). Its key design choice: TypeScript is a superset of JavaScript. Every JavaScript program is valid TypeScript, and the compiler simply erases the types and outputs plain JavaScript. Types exist to catch mistakes early and to power editor features such as autocompletion and safe renames.

The project moved to GitHub in 2014, and adoption took off when Google's Angular 2 chose TypeScript in 2015. Today most large JavaScript projects and frameworks are written in TypeScript or ship TypeScript types.

Timeline of major versions

1. TypeScript 7.1Oct 2026Upcoming

   • Beta announced October 2026; expected to bring the new compiler API for tools such as linters
2. TypeScript 7.0Jul 2026Current

   • A native compiler written in Go with multithreading: full builds typically 8–12× faster than 6.0
   • Keeps 6.0's defaults (strict on) and turns the deprecated options into errors; no compiler API yet
3. TypeScript 6.0Mar 2026Supported

   • The last release of the original JavaScript-based compiler, a bridge to 7.0
   • New defaults: strict: true, module: esnext, latest target; legacy options such as target: es5 and baseUrl deprecated
4. TypeScript 5.0Mar 2023Historic

   • Standard ECMAScript decorators, const type parameters, moduleResolution: bundler
5. TypeScript 4.9Nov 2022Historic

   • The satisfies operator: check a value against a type without widening it
6. TypeScript 4.1Nov 2020Historic

   • Template literal types such as `on${Capitalize<E>}` and key remapping in mapped types
7. TypeScript 4.0Aug 2020Historic

   • Variadic tuple types and labeled tuple elements
8. TypeScript 3.0Jul 2018Historic

   • The unknown type, project references for large repositories, richer tuples in rest parameters
9. TypeScript 2.0Sep 2016Historic

   • strictNullChecks (non-nullable types), control-flow based type narrowing, the never type
10. TypeScript 1.0Apr 2014Historic

    • First stable release, announced at Microsoft Build
11. TypeScript 0.8Oct 2012Historic

    • First public release

TypeScript does not follow semantic versioning: a new minor version (5.1, 5.2, …) ships about every three months, and any release can include small breaking changes. The jump from 6 to 7 marks the switch to the new compiler.

How TypeScript modernized

• Stricter by default. Early TypeScript was lenient. strictNullChecks (2.0) and the strict family of options became best practice, and 6.0 finally made strict the default.
• A type system that models real JavaScript. Union types, narrowing, mapped and conditional types (2.x), template literal types (4.1) and satisfies (4.9) let TypeScript describe even very dynamic code precisely.
• Following the standard. TypeScript adopts ECMAScript features as they reach stage 3, and 5.0 switched to the standard decorators.
• A 10× faster compiler. Announced in March 2025, the native Go port (Project "Corsa") shipped as TypeScript 7.0 in July 2026, cutting build and editor wait times on big projects from minutes to seconds.
• Running TypeScript directly. Modern runtimes such as Deno, Bun and recent Node.js versions can run .ts files by stripping the types, without a separate build step.

TypeScript 5 vs 6 vs 7

Which version should you use?

• New projects: TypeScript 7 for the speed. If a tool you depend on (some linters and bundler plugins) needs the compiler API, also install the @typescript/typescript6 package for that tool until 7.1.
• Existing projects: upgrade to 6.0 first and fix its deprecation warnings; then 7.0 compiles the same code without surprises.
• This tutorial: examples run in your browser after the types are stripped, and every example is type-checked with tsc in strict mode when we build the lesson.

Official resources

• typescriptlang.org and the TypeScript Handbook
• Release notes for every version
• TypeScript team blog: release announcements
• TypeScript on GitHub and the native compiler repository
• TypeScript roadmap

Last reviewed 21 October 2026. Release and support dates come from the official release pages linked above.