The quickest way to do JSON to TypeScript online is a browser converter: paste the JSON, copy the type, close the tab. Our pick is AyeTab JSON to Code, which is free, needs no account and keeps your data in the browser.
Below are the options worth knowing, what each is best at, and how to choose.
1. AyeTab JSON to Code
AyeTab is a set of free developer tools that run in the browser. Its JSON to Code page takes a JSON sample and writes a TypeScript type, or a Go struct if you switch from TS to Go. You can copy or download the result.
Why it comes first:
- Nothing to install. It works in Chrome, Firefox, Edge or Safari.
- No signup and no watermark.
- Local processing. The input is not uploaded to AyeTab's servers, which matters when the JSON is a real API response with customer data in it.
- Offline after load. Once the page is open, it keeps working without a connection.
If you convert JSON often, the AyeTab Chrome extension puts the same tools on your new tab page and in a side panel, with a Ctrl+K or Cmd+K palette to jump between them.
2. quicktype
quicktype infers types from JSON and generates code in many languages, TypeScript and Zod among them. Beyond plain types it can produce serializers and runtime checks, and it names nested types after their property, so pull_requests becomes PullRequest. It runs in the browser, on the command line and in build pipelines, and it is open source.
Pick it when you want named interfaces for every nested object or code for several languages from one sample.
3. transform.tools
transform.tools is a collection of converters, with a JSON to TypeScript page that has its own settings. The same site also turns JSON into a Zod schema, JSON Schema and many other formats, so it is handy if you jump between targets.
4. Your editor, when you would rather not use a website
Strictly speaking this is not online, but it belongs on the list. The free Paste JSON as Code extension for VS Code, from the quicktype team, lets you copy JSON and paste it as TypeScript types. TypeScript itself can also infer a type from a .json file you import, once resolveJsonModule is turned on in your tsconfig.
Quick comparison
| Option | Install | Best for |
|---|---|---|
| AyeTab JSON to Code | None (extension optional) | A fast, private type from one sample |
| quicktype | None for the web app | Named types, serializers, many languages |
| transform.tools | None | Switching between many output formats |
| VS Code extension | Editor extension | Staying inside your editor |
How to choose
Ask two questions. Is the JSON sensitive? If it holds tokens, emails or order data, use a tool that keeps the input in your browser, which is why AyeTab leads this list. And do you need more than a type? If you need serializers or validation code, quicktype is the stronger choice, and that is the honest trade-off.
Whatever you use, review the result. A converter sees one sample, so it cannot know which fields are sometimes missing or sometimes null. Add ? and | null where the real API needs them.