JSON to TypeScript Interface

Generate TypeScript interfaces from any JSON object in one click. Paste a REST API response, a config object, or any JSON data — the tool walks the structure and outputs typed interfaces for every nested object. Null values are typed as null or optionally marked with ?. Arrays infer their element type from the first item. Works with deeply nested structures and generates multiple interfaces automatically.

How nested objects are handled

Each nested object becomes its own named interface. For example, if the root has an address field containing an object, the tool generates an Address interface and references it in the parent. Interfaces are output in dependency order — child types first, then parent types.

What about arrays?

Arrays are typed based on the first element. An array of strings becomes string[]. An array of objects generates a new interface (e.g., TagsItem[]) and that interface is defined separately. Empty arrays become unknown[].

JSON to TypeScript vs JSON to Zod

TypeScript interfaces are pure type annotations — they exist only at compile time and are erased at runtime. Zod schemas are runtime validators that also infer TypeScript types. Use interfaces for simple typing; use Zod when you need to validate data at runtime (e.g., parsing API responses in production).