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JSON to TypeScript Converter

Turn JSON into TypeScript interfaces instantly — plus Go structs and PHP classes — with nested objects handled automatically. Free, browser-based.

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💡 How to use

  • Paste a JSON object or array, pick your target language, and generate.
  • Nested objects become their own named interfaces/structs automatically.
  • Runs in your browser — your JSON is never uploaded.

Free JSON to TypeScript Converter

Turn any JSON into TypeScript interfaces instantly — plus Go structs and PHP classes. Paste your JSON, name the root type, and copy ready-to-use definitions with nested objects handled automatically. Free, no sign-up, and runs entirely in your browser.

What does JSON to TypeScript do?

This tool reads a JSON object or API response and generates matching type definitions, so you get compile-time safety and editor autocomplete instead of guessing an object's shape. It infers each field's type from your data — strings, numbers, booleans, arrays, and nested objects — and produces clean interfaces you can drop straight into your codebase, saving the tedious work of writing them by hand.

Output formats supported

Generate types for several languages from the same JSON:

  • TypeScript interface — the most common choice for typing API responses.
  • TypeScript type alias — for when you prefer type over interface.
  • Go struct — with json tags for encoding and decoding.
  • PHP class — a simple class with public properties.

How to use the converter

It is instant:

  • Paste a JSON object, or an array of objects, into the input.
  • Pick your output language and name the root type.
  • Optionally mark properties as optional.
  • Copy the generated types into your project.

How nested objects are handled

When your JSON contains nested objects, the tool creates a separate, named type for each one and references it from the parent — exactly how you would structure the types by hand. Arrays are typed by their first element, so an array of objects becomes an array of a generated interface. This keeps the output readable and reusable rather than producing one giant inline type.

Why type your API responses

Typing the data that flows into your app catches a whole class of bugs before they ship. With generated interfaces, your editor autocompletes field names, flags typos, and warns you when an API field is missing or the wrong type. It also serves as living documentation of an endpoint's shape, which is invaluable when you return to code months later or hand it to a teammate.

Pro tip

Paste a real response from your API rather than a hand-written sample, so the generated types reflect exactly what the server sends. If some fields are sometimes absent, enable 'Optional properties' so the types allow it. For formatting or validating the JSON first, use our JSON Formatter.

FAQ

Is this JSON to TypeScript tool free and private?
Yes. It is completely free and runs entirely in your browser, so your JSON is never uploaded or stored.
How do I convert JSON to a TypeScript interface?
Paste your JSON, keep the output set to 'TypeScript interface', name the root type, and copy the generated code. Nested objects become their own interfaces automatically.
Can it generate Go structs or PHP classes?
Yes. Choose Go struct (with json tags) or PHP class from the output menu to generate types for those languages from the same JSON.
How are nested objects and arrays handled?
Nested objects each get their own named type that the parent references. Arrays are typed by their first element, so an array of objects becomes an array of a generated interface.
Can I mark fields as optional?
Yes. Enable 'Optional properties' to add the optional marker to each field, which is useful when some API fields are not always present.
What if my JSON is invalid?
The tool shows a clear error message pointing to the problem. Fix the JSON — a formatter or validator can help — and the types regenerate instantly.
Does it work with an array of objects?
Yes. Paste an array and the tool infers the type from the first object, generating an interface you can use for the whole list.

Related tools

Pro tip: pair this tool with Upside Down Text Generator and Text Similarity Checker for a faster SEO workflow.