JSON to TypeScript Interface

About This Tool

The JSON to TypeScript Interface Generator automatically creates TypeScript interface definitions from any JSON object. Paste your JSON and get a typed interface instantly — useful when working with API responses or configuration objects that don't yet have TypeScript types.

The tool infers: string, number, boolean, null, nested objects (as named sub-interfaces), and arrays (as T[]). Object keys containing spaces or special characters are automatically quoted. All processing runs in your browser — no JSON data is sent to any server.

How to Use

1. Paste your JSON object into the input area, or click Sample to load an example.
2. Optionally set the Interface Name (defaults to "Root").
3. Click Generate to create the TypeScript interface.
4. Click Copy to copy the interface definition to your clipboard.

Use Cases

Frontend developers paste API response JSON to generate TypeScript interfaces for type-safe data handling. Backend developers generate types for configuration objects and database schemas. Teams consuming third-party REST APIs without official TypeScript SDKs generate initial type definitions from sample responses. Developers onboarding to an existing JavaScript project add types to untyped data structures.

FAQ

• Does it support arrays of objects? — Yes. An array of objects is typed as an interface with T[] for the array type, and a sub-interface is generated for the object shape.
• Are optional fields detected? — No. All fields are required by default. Add ? manually for fields that may be absent.
• What about null values? — Fields with null values are typed as null. You may want to widen these to string | null or number | null after generation.