Paste TypeScript and get the same type errors as running tsc, with the error code, line and column. The official TypeScript compiler and its standard and browser type libraries load once, then everything is checked on your device. Turn on “Show the compiled JavaScript” to see what your code becomes.
loading toolHow to use the typescript checker
- Paste your code into the box (or tap Try a sample).
- Read the list of problems: ✕ marks an error, ! a warning.
- Tap Show next to a problem to jump to that line, fix it, and watch the list update.
Good to know
- TS2322 means “this value has the wrong type”, TS2339 “this property does not exist”, TS7006 “give this parameter a type”.
- The first load downloads about 3 MB; after that it is cached by your browser.
Questions
Which TypeScript version is it?
TypeScript 5.6 with the ES2022 and DOM type libraries, in strict mode by default (you can switch strict mode off).
Can I import npm packages?
Imports of packages like react show a warning, because their type files are not available here. Paste the types you need into the box, or check those files in your own project.
Does my code get uploaded?
No. The checker or runtime is downloaded once from a public CDN (jsDelivr or cdnjs) and then runs inside your browser. Your code never leaves your device.
Is my data private?
Yes. Everything happens inside your own browser: nothing you type or choose is uploaded to us or anyone else.
Is it free?
Completely free, with no sign-up, no watermark and no limit on how many times you use it. Light ads keep the site running.
