JSON to TypeScript
Generate TypeScript interfaces from a JSON object or API response.
Typing an API response by hand is tedious and error-prone — you stare at a JSON payload and transcribe every field into an interface, guessing types and missing optional properties. Generating the types from the actual data is faster and more accurate, and it's the first step most developers take when integrating a new endpoint.
Paste a JSON object and this tool infers a set of TypeScript interfaces, naming nested objects, detecting arrays and their element types, and falling back to sensible types for nulls and mixed values. Copy the result straight into your codebase as a starting point, then refine optionals and unions as you learn the API.
How to use JSON to TypeScript
- 1
Paste a JSON object
An API response or sample payload.
- 2
Get TypeScript interfaces
Types inferred for every field and nested object.
- 3
Copy into your code
Refine optionals and unions as needed.
Features
- Infers types for strings, numbers, booleans, arrays and objects
- Names and extracts nested interfaces
- Handles arrays of objects
Frequently asked questions
Common mistakes to avoid
- Trusting the generated types as complete — a single sample can't reveal every optional field or edge case.
- Generating from an error response instead of a successful one, producing the wrong shape.
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