How to Convert JSON to TypeScript
JSON to TypeScript
When to Generate TypeScript from JSON
Bootstrap API response types, config interfaces, or fixture types from sample JSON. Faster than hand-writing interfaces for nested structures.
How Inference Works
Types are inferred from the sample values in your JSON. Optional fields, unions, and nullable properties require representative samples — a single object may mark all keys as required.
Common Mistakes
- Using one sample when fields are optional in the real API
- Expecting discriminated unions from heterogeneous arrays
- Keys with special characters — they are quoted in the output interface
Frequently asked questions
Are all properties required?
Yes, based on the sample JSON. If a field is missing from the sample, it will not appear in the interface.
Can I customize the root type name?
Yes. Set the Root type name in Tool Settings before running.