JSON to TypeScript

Your data never leaves your browser

Generate TypeScript interfaces from JSON data automatically.

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About JSON to TypeScript

Paste any JSON and instantly get TypeScript type definitions. The tool infers types from values — strings, numbers, booleans, arrays, nested objects — and generates a clean interface or type alias you can paste directly into your codebase.

How to use

  1. Paste a JSON object or array into the input panel.
  2. The TypeScript interface appears instantly in the output panel.
  3. Click Copy to paste the types into your TypeScript project.

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Frequently Asked Questions

FAQs about JSON to TypeScript

How does type inference work?

The tool examines each value in your JSON: strings become `string`, numbers become `number`, booleans become `boolean`, null becomes `null`, arrays infer element types, and objects become nested interfaces.

Does it handle arrays?

Yes. Arrays with a single element type produce `type[]`. Mixed arrays produce union types like `(string | number)[]`.

Can I rename the root type?

The generated type is named "Root" by default. You can rename it after copying to your codebase.

Does it handle optional fields?

Currently all fields are treated as required. If you need optional fields, add the `?` modifier manually after generation.

Is my data safe?

Yes. All type inference happens in your browser. No data is sent to any server.