JSON to TypeScript Converter

Use JSON to TypeScript Converter, review the result, and keep the original until the output is checked.

Input JSON
JSON Input
Converted TypeScript
TypeScript Output
Click "Convert to TypeScript" to see converted TypeScript here...
100% browser-side processing — your data is never uploaded to any server. · Per-tool input limit: 1 MB
100% browser-based No upload to server Free to use

Frequently Asked Questions About JSON to TypeScript Converter

Can it fix JSON with trailing commas or comments?

Yes. The repair step removes trailing commas, comments and a byte-order mark, turns single-quoted strings into double-quoted ones and quotes bare member names, then re-reads the document. Values it cannot infer, such as a Python True or a missing closing brace, still need a manual edit.

Why do large numbers change when I format JSON?

JavaScript numbers are IEEE-754 doubles, so most parsers rewrite an integer above 2^53 and lose its tail digits. This page keeps those long literals exactly as you typed them, but a parser elsewhere in your stack will not, so keep such ids as strings in the source document.

Should I trust generated types in production?

Treat them as a starting point. Rename interfaces to your domain vocabulary and re-check nullable fields against the API contract.

Are arrays of objects handled?

Yes. A uniform array produces one element type, while mixed arrays widen to a union or a general type.

What is JSON?

JSON (JavaScript Object Notation) is a lightweight data-interchange format. It uses objects {}, arrays [], strings, numbers, booleans, and null.

Why format JSON?

API responses and config files are often minified. The JSON to TypeScript Converter expands them with indentation so you can spot nested keys, validate structure, and debug faster.