Paste JSON or a JSON Schema and generate strongly-typed models for nine languages — powered by the quicktype engine, running entirely in your browser.
Generated types will appear here.
Hand-writing model types for an API response is tedious and error-prone. This tool infers the shape of your JSON — nested objects, arrays, optional fields, unions and enums — and emits idiomatic code: TypeScript interfaces or type aliases, a Go struct with JSON tags, a Rust struct with serde derives, a Python dataclass or Pydantic model, a C#, Swift, Kotlin or Java class, or a runtime-validating Zod schema. Each language exposes a few useful options, such as interfaces vs. type aliases, Pydantic vs. dataclasses, or the JSON framework for C#.
The generation is done by quicktype, a mature open-source type generator. Most sites that offer it run it on a server, meaning your payloads are uploaded. Here the quicktype engine is compiled to a single self-hosted JavaScript bundle and loaded straight into your browser tab, so the work happens locally — nothing is sent anywhere.
A JSON sample is the quickest path: paste a representative response and the types are inferred from its structure. A JSON Schema gives you exact control — required vs. optional fields, enums, formats — and is generated verbatim rather than inferred. Use whichever you have. External $refs are not fetched, keeping the tool fully offline.
Yes. There is no upload step and no account. API payloads and schemas are processed entirely inside your browser — open the network tab and watch: no request carries your data. Once the page has loaded, the generator works offline.
