JSON to TypeScript
Infer a TypeScript type alias from a JSON sample, including nested objects and array unions.
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How to use JSON to TypeScript
Use a sample response as a starting point for TypeScript types. Property names are quoted safely, primitives become broad types, and mixed arrays receive a union of their observed item shapes.
- Paste representative JSON and choose an uppercase type name.
- Select Run tool to infer a draft TypeScript type alias.
- Review the result, then copy it or download the generated file.
Good to know
- Up to 100,000 input characters, 10,000 values, and 40 nesting levels. Standard JSON numbers use JavaScript precision; duplicate keys retain their last value.
- A sample cannot reveal optional fields or every possible value. Empty arrays and arrays with over 20 distinct inferred shapes become unknown[]; review generated types.
Common questions
Is this a runtime validator?
No. A TypeScript type is a compile-time declaration and does not validate incoming data.
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