How does the converter pick types for each field?

It reads the value of each key and infers the matching TypeScript type, so numbers become number, text becomes string, and true or false becomes boolean. Objects turn into their own named interfaces.

Can it handle nested objects and arrays?

Yes. Each nested object gets its own interface named after its key, and arrays are typed from the elements they contain. The top level is always named Root.

Is my JSON uploaded anywhere?

No. The conversion runs entirely in your browser, so your data never leaves your device and nothing is stored or sent to a server.

JSON to TypeScript Converter

Input

Output

What this tool does

The JSON to TypeScript Converter turns raw JSON into ready to use TypeScript interfaces. Paste an object or array and it generates a typed interface called Root, plus separate interfaces for any nested objects it finds. It is built for frontend and backend developers who work with API responses, config files, or sample payloads and want strong typing without writing every interface by hand.

How to use it

Paste or type your JSON into the text box.
Make sure the JSON is valid, with quoted keys and matching brackets.
Press Convert to generate the TypeScript interfaces.
Copy the result straight into your project.

A quick example

Paste this:

{"id":1,"name":"Ada","address":{"city":"Paris"}}

You get an interface Root with id typed as number and name typed as string, plus a nested Address interface holding city as string. Each nested object becomes its own interface, which keeps the output readable and easy to reuse across your codebase. A common gotcha is trailing commas or single quotes, which are valid in JavaScript but not in JSON, so clean those up first if the converter reports a problem.

This tool runs entirely in your browser. It is private, free, and needs no sign-up.

Frequently asked questions

How does the converter pick types for each field?: It reads the value of each key and infers the matching TypeScript type, so numbers become number, text becomes string, and true or false becomes boolean. Objects turn into their own named interfaces.
Can it handle nested objects and arrays?: Yes. Each nested object gets its own interface named after its key, and arrays are typed from the elements they contain. The top level is always named Root.
Is my JSON uploaded anywhere?: No. The conversion runs entirely in your browser, so your data never leaves your device and nothing is stored or sent to a server.

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Last updated: June 17, 2026