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JSON to TypeScript Generator

Paste JSON and get clean TypeScript interfaces. Optionally emit runtime type guards.

JSON sample
TypeScript

How to generate TypeScript from JSON

  1. 1
    Paste your JSONDrop an API response or sample object into the editor.
  2. 2
    Set a root namePick a name like User or ApiResponse for the top-level interface.
  3. 3
    Copy the outputCopy the generated .ts file or download it directly to your repo.

Frequently asked questions

Does it infer optional vs required fields?
Yes. Fields missing from any sample item in an array become optional with `?`.
Does it handle union types?
Yes — mixed primitives in an array become a union (e.g. `Array<string | number>`).
Can it produce runtime type guards?
Yes. Tick "runtime typecheck" to also emit validator functions you can call at runtime.
Does it generate types or interfaces?
Interfaces by default for the top level, with nested types where unions or aliases are clearer.
Is my JSON sent anywhere?
It's sent to our generator service, processed in memory, and discarded — never stored.
What if my JSON has nulls?
Nulls become `null` in the type union, so `string | null` is preserved cleanly.

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