JSON to TypeScript Interfaces

Stop manually typing TypeScript interfaces from API responses. Paste any JSON — no matter how deeply nested — and instantly get production-ready TypeScript interfaces. Handles arrays, nested objects, null values, and special key names. Runs entirely in your browser, zero upload.

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Comment utiliser JSON to TypeScript Interfaces

Accomplissez votre tâche parfaitement en trois étapes simples.

Paste Your JSON

Paste a raw API response, config file, or any JSON object into the left panel.

Configure Options

Set your root interface name, choose export/optional preferences, and switch between interface and type alias styles.

Copy or Download

Instantly copy the generated TypeScript to your clipboard or download as a .ts file.

FAQ

Tout ce que vous devez savoir sur le JSON to TypeScript Interfaces.

Does it handle deeply nested objects?

Yes. The generator recursively traverses all nested objects and arrays, creating a separate named interface for each one — so you get clean, reusable types rather than deeply nested inline types.

What happens with null values?

When 'Make nullable fields optional' is on, null fields are typed as 'string | null' with a '?' modifier. When off, null fields are typed as 'null' — useful when you want to be strict about what's truly unknown.

What's the difference between interface and type alias?

In TypeScript, interfaces are open (can be extended/merged) while type aliases are closed. For most API response shapes, both are equivalent. Use interface for domain models you might extend; use type for strict data shapes.

Does it handle arrays at the root?

Yes. If you paste an array like [{...}, {...}], the generator creates interfaces for the item type and exports a root type alias like 'type Users = User[]'.