JSON to TypeScript Interface
Turn any JSON sample into typed TS interfaces.
How to use
- 1 Paste a representative JSON object or array into the input.
- 2 Optionally rename the root interface.
- 3 Review the generated TypeScript interfaces on the right.
- 4 Copy the output into your project.
About JSON to TypeScript Interface
The JSON to TypeScript Interface tool turns a sample of JSON into ready-to-use TypeScript type definitions.
Instead of hand-writing interfaces for an API response or a config file, paste the JSON and get clean, named interfaces in seconds — a huge time-saver when you are wiring up a typed client or documenting a payload shape.
The converter walks the whole structure.
Primitive fields become string, number or boolean; nested objects are extracted into their own named interfaces and referenced by property, keeping the output readable rather than deeply inlined.
Arrays are inspected to infer an element type, and when elements differ the tool produces a union such as (string | number)[].
Property names that are not valid TypeScript identifiers — like keys with hyphens — are automatically quoted so the result always compiles.
You can also set the name of the root interface to match your domain.
Everything runs locally in your browser, so even sensitive or proprietary payloads never leave your machine.
The output updates live as you type or paste, making it easy to tweak your sample and immediately see the resulting types.
Copy the generated interfaces straight into your codebase and start getting autocomplete and type-checking on your data.
FAQ
How are nested objects handled?
Each nested object is extracted into its own named interface and referenced by property, so the output stays readable instead of deeply inlined.
What happens with arrays of mixed types?
The tool inspects array elements and produces a union element type, such as (string | number)[], when the items are not all the same type.
Is my JSON uploaded anywhere?
No. Conversion runs entirely in your browser, so your JSON never leaves your device.