JSON to TypeScript Converter

JSON to TypeScript Converter generates TypeScript interfaces or type aliases from a JSON sample, such as an API response or test fixture. Paste JSON and it extracts nested objects into named types, merges arrays of objects so fields missing from some items become optional, turns mixed arrays into unions, and suggests enums for small repeated sets of strings. You can set the root type name, switch between interfaces and type aliases, choose 2- or 4-space indent, and decide whether null fields stay null or become optional. Output updates as you type and can be copied or downloaded as a .ts file. Conversion runs in the browser, and your JSON is not posted to a conversion API. Free to use.