JSON → TypeScript Interface
Nested objects, unions, null handling
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Quick guide
What can JSON to TypeScript Interface help you do?
Free online JSON to TypeScript interface converter. Handles nested objects, arrays, null, and union types. Copy and paste into your project.
Best for
Useful for quick file work, text cleanup, calculations, content creation, and website or AI checks.
How to use it
Open the tool, enter or upload what it asks for, then copy or download the result directly.
Privacy and limits
Most tools run in your browser with no sign-in. Very large files or older devices may hit browser memory limits.
Frequently Asked Questions
How is null handled?
Inferred as null. If another item has the same field, it merges as union (string | null).
Arrays with multiple types?
Auto-merged into union: (string | number)[].
Deep nesting?
Unlimited. Each level produces a sub-interface referenced by name.