Manually writing TypeScript interfaces for API responses is tedious and error-prone. This JSON to TypeScript generator infers types from your JSON data automatically — handling nested objects, arrays, nullable fields, and optional properties. Paste a JSON response and get production-ready TypeScript interfaces instantly.

The inference engine handles edge cases that simpler tools miss: arrays of objects are merged into a single interface with optional fields for keys that don't appear in every item, null values produce union types (string | null), and deeply nested structures generate separate named interfaces rather than inline types.

Toggle between interface and type syntax depending on your project conventions. Enable export for module-ready types, or readonly for immutable data structures. The root interface name is configurable — change it from "Root" to match your domain model.

Tips

Paste a real API response rather than writing JSON by hand — the generator handles the exact shape your code needs to work with.
For APIs that return arrays at the top level, the generator creates a type alias for the array and a separate interface for the item shape.
Use the readonly option for data that comes from APIs and shouldn't be mutated in your frontend state.
If your JSON has fields that are sometimes missing, wrap multiple response examples in an array — the generator will detect optional fields automatically.