JSON to TypeScript Interface
Convert any JSON object into TypeScript interfaces instantly. Handles nested objects, arrays, and mixed types.
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Buy me a coffeeWhat is JSON to TypeScript Interface?
The JSON to TypeScript Interface Generator converts any JSON object into properly typed TypeScript interfaces. Paste your JSON — from an API response, config file, or database record — and get clean, ready-to-use TypeScript type definitions in seconds. Everything runs in your browser; your data never leaves your device.
How to Use JSON to TypeScript Interface
Common Use Cases
- Typing API responses without writing interfaces by hand
- Generating types for JSON config files
- Bootstrapping TypeScript definitions from existing data
- Exploring unfamiliar JSON structures as typed interfaces
- Speeding up TypeScript migration from plain JavaScript
Frequently Asked Questions
How are nested objects handled?
Each nested object gets its own named interface. The interface name is derived from the property key (e.g. a key "address" becomes "Address"). All sub-interfaces are output above the root interface.
What happens with arrays?
Arrays of a single primitive type become e.g. string[]. Arrays of objects generate a sub-interface and become SubInterface[]. Mixed-type arrays produce a union type like (string | number)[].
How is null handled?
A null value produces the type null. If you want to make fields nullable, you can manually change them to string | null after generation.
Is my data sent to a server?
No. All conversion logic runs entirely in your browser. Your JSON never leaves your device.