JSON to TypeScript

What it does

Turns a sample of JSON into TypeScript type definitions — interfaces for the objects, with inferred field types — using quicktype. Paste a representative response and the types appear beside it.

Why generate them here

The JSON you would paste to generate types is usually a real API response, and it often carries tokens, email addresses, internal IDs, or customer data. Online generators upload that sample to a server. This one runs entirely in your browser, so the response you paste to scaffold your types never leaves your machine.

It infers from the sample, so read the result

Types are inferred from the example you give. A field that is null in your sample, or present in one object but missing from another, can only be guessed at — so treat the output as a strong first draft to refine (optional fields, unions, enums), not a contract. The more representative the sample, the better the types.

When to use it

Scaffolding types for a third-party API you are integrating, a config file's shape, a fixture, or a webhook payload — anywhere you have an example and want a typed starting point fast.

Privacy

Type generation runs in your browser (quicktype is loaded locally). The JSON you paste is never uploaded, and the page works offline after the first load.