JSON
JSON to TypeScript
Turn a representative JSON sample into a named TypeScript type for a draft interface.
How this tool works
Nested objects and arrays become typed structures. Different observed values form unions, and a property absent from some observed array objects becomes optional.
Example-driven inference cannot discover values or fields absent from the sample. Review generated types against the real API contract.
Examples
- Infer a nested order response.
- Observe optional fields across array elements.
- Preserve null as a union member.
Common use cases
Worked synthetic example
Valid example
{"order":{"id":7,"note":null}}
Expected: An Order shape with numeric id and null note. The type reflects only the supplied sample; another note value would change the inferred union.
Failure or warning to recognize
Warning / interpretation
A single example omits a field that exists in real responses.
Expected: A sample missing a real response field still generates a type without that field; compare it with the API contract.