JSON input
valid
TypeScript output
Quicktype is a multi-language type generator (TS, Go, Python, Rust, Swift, Java, C#) with a CLI and library API. This tool is a hosted browser converter focused on JSON → TypeScript / Zod / Valibot. Use the converter below; the body explains where each one wins.
Quicktype (quicktype.io) is the heavyweight in this category. Its core engine generates types in 9+ target languages, accepts JSON, JSON Schema, GraphQL, and TypeScript as input, ships a CLI, an npm library (quicktype-core), and IDE integrations. If you need to generate Go structs, Rust enums, or Swift Codable types from the same JSON sample your TypeScript code consumes — or you want to run the conversion inside a build pipeline against a directory of fixtures — Quicktype is built for that workflow and this tool is not.
Where Quicktype is broad, this tool is narrow on purpose. It targets a single wedge: JSON pasted into a browser, converted in-place to a TypeScript interface (or type alias), a Zod schema, or a Valibot schema, with no install, no upload, no signup, and no signed-in account. The same shape-walk algorithm produces all three outputs from one paste — toggle at the top of the result pane. Quicktype's TypeScript renderer is more sophisticated for edge cases (custom rendering rules, more configurable optional inference); the trade-off is a CLI install or a JavaScript dependency.
Honest tradeoffs: Quicktype is the right call for multi-language code generation, build-pipeline integration, JSON Schema as input, or large codebases that want repeatable conversion. This tool is the right call when you want a single TypeScript / Zod / Valibot output from one browser paste, when privacy matters (everything stays in your tab), or when your JSON came from a real API and you want a quick type for one consumer. Both are free; pick by the job, not the brand.