Does this JSON to TypeScript tool upload my JSON?

No. JSON parsing and TypeScript generation run locally in your browser, and the tool does not send input to a server.

Can this generate perfect production types?

It generates a practical first draft from example JSON. Review the result before using it as a stable public API contract.

How are arrays of objects handled?

The generator merges object fields across array items and marks fields as optional when they are missing from some items.

What happens with null values?

Null values are preserved as null in the generated union types so you can decide whether the API should allow them.

JSON to TypeScript Types Generator

What this JSON to TypeScript generator is for

Use this tool when you have an example API response, fixture, mock payload, or backend contract and want a TypeScript starting point quickly.

The generator runs locally in the browser. Your JSON is parsed on your device and is not uploaded to a server.

How to use it

Paste valid JSON, choose a root type name, and generate either an interface for root objects or a type alias. The output supports nested objects, arrays, null values, and merged fields for arrays of objects.

Treat the generated TypeScript as a starting point. Example JSON rarely captures every possible production value, so review optional fields, nullable fields, and union types before committing the result.

Use the CSV to JSON Converter when starting from tabular data, the JSON Formatter to validate or format payloads first, the JSON Pointer Resolver for exact RFC 6901 locations, the JSONPath Tester to inspect nested fields, the JSON Schema Generator when you need a validation draft, and the Text Diff Checker to compare two generated versions after an API response changes.

JSON to TypeScript Types Generator