JSON to TypeScript Converter

Reference

Why convert JSON to TypeScript?

TypeScript's type system catches errors at compile time that would otherwise surface as runtime bugs in JavaScript. When working with API responses, configuration files, or any JSON data, defining TypeScript interface or type declarations gives you autocompletion, type checking, and refactoring safety in your editor. This tool analyzes the structure of your JSON — detecting objects, arrays, strings, numbers, booleans, and null values — and generates accurate TypeScript types that match the data shape, including proper handling of nested objects and arrays of mixed types.

TypeScript types from JSON

The converter maps JSON values to TypeScript types: string → string, number → number, boolean → boolean, null → null. Objects become interface declarations with a named type for each nested object. Arrays are typed as Type[], and if array elements have different shapes, the converter creates a union type. The export toggle adds export keywords for use in modules, and readonly marks all properties as readonly for immutable data patterns.

Privacy

All conversion runs 100% in your browser. No JSON data is sent to any server.