JSON to TypeScript
Convert JSON to TypeScript interfaces automatically. Nested objects become interfaces, arrays become typed arrays, and nullable fields become unions. Runs entirely in your browser.
JSON input
Generated TypeScript
What this tool does
This JSON to TypeScript converter takes a JSON document and generates TypeScript type definitions from its shape. It runs entirely in your browser — your data never leaves the page.
How it works
1. Infer types. Every value is inspected: strings, numbers, booleans, null, arrays and nested objects.
2. Merge shapes. Array items are merged so optional fields stay optional.
3. Name fields. Keys become valid target-language identifiers.
4. Emit code. TypeScript definitions preserve original JSON keys.