Generator Knowledge Base

JSON to TypeScript Interface: Generate TS Types Instantly

Generate TypeScript interfaces and type aliases from any JSON. Handles nested objects, optional fields, and union types. Free online, 100% browser-based.

Stop Writing TypeScript Interfaces by Hand

When working with third-party APIs, copying JSON responses and manually writing TypeScript interfaces wastes developer time and introduces bugs. Our generator analyzes any JSON object and produces accurate, nested interfaces in seconds.

How Type Inference Works

  • string values → string type
  • Integer values → number type
  • true / false → boolean type
  • null → null or optional field (?)
  • Nested objects → separate named interface declarations
  • Arrays of objects → typed array ChildType[]
  • Mixed arrays → union type (string | number)[]

Generating Zod Schemas Too

Switch to the Zod tab to also get a runtime validation schema that mirrors your TypeScript interface. Use z.infer<typeof schema> for zero-duplication type safety.

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Frequently Asked Questions

Can I generate a type alias instead of an interface?

Yes. Use the Output dropdown in the toolbar to switch between interface and type alias output.

Does the generator add export keywords?

Yes, by default all interfaces are exported. Toggle the export checkbox in the toolbar to change this.

What happens with empty arrays?

Empty JSON arrays generate unknown[] with a comment indicating the type could not be inferred.

Can I customise the root interface name?

Yes. Edit the "Root name" field in the toolbar to use any valid TypeScript identifier.

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