JSON to TypeScript – Generate Interfaces

Generate TypeScript interfaces from JSON data automatically. Configure the root interface name.

JSON Input
TypeScript Output

What is JSON to TypeScript Conversion?

The JSON to TypeScript generator converts any JSON document into clean, copy-ready TypeScript interfaces — including nested objects, arrays, and inferred optionality — in one click. Paste an API response, sample payload, or config and get accurate types you can paste straight into your editor. Generation happens entirely in your browser: sample data, which often mirrors real user records, never leaves your device.

Interface vs. type — what the generator emits.

The generator infers structure intelligently — objects become named interfaces, arrays derive element types, and keys missing from some objects are marked optional (?) rather than breaking the type. Set the root interface name to match your domain model, then copy the output or download it as a .ts file. Because it's client-side, you can type internal or pre-release payloads without sharing them with an online service.

How to generate TypeScript interfaces.

  1. Paste your JSON — an API response, sample payload, or config
  2. Set the Root interface name (defaults to Root)
  3. Click "Generate Types" to infer interfaces locally
  4. Copy or download the emitted .ts interfaces

Need to clean the sample first? Send it through "Open in" to the Formatter or Repair tool.

Related JSON tools.

Pair type generation with validation and contracts:

FAQ.

What does the generator output — interfaces or types?

Named TypeScript interface declarations by default: one per object shape, with arrays derived as element types and a root interface you name.

How are missing or inconsistent keys handled?

Keys absent from some objects are emitted as optional (key?: type), so a union of sample records produces a usable, non-breaking type.

Can I rename the root interface?

Yes — set the Root interface name before generating (defaults to Root); nested interfaces are named automatically from their keys.

Is my JSON uploaded to generate types?

No. Type inference runs locally in your browser. Data that mirrors real user records or unreleased features stays on your device.

Why generate types from JSON instead of writing them by hand?

It's instant and accurate for large or deeply nested payloads, and it guarantees your types match the actual API response you pasted.

Looking for a different transformation? Explore thefull JSON toolkit— 11 free, private, in-browser tools that never upload your data.