JSON to TypeScript
Generate TypeScript interfaces and types from JSON
JSON Input
TypeScript Output
Generate exact TypeScript types from real payloads
Hand-typing interfaces from an API response is error-prone — you forget a field, get a type wrong, miss a nested array. Generating TypeScript directly from a sample payload produces named interfaces, typed arrays, and nested types that match the data exactly, ready to paste into your code.
Use the converter when you need to
Type a new API response
Drop a sample response in, get back interfaces you can import without writing a single property by hand.
Catch shape changes during integration
Regenerate types when the API response shape evolves and let TypeScript surface every downstream break.
Type third-party SDK responses without docs
When an SDK lacks types, generate them from a real response and gain autocomplete instantly.
How to generate TypeScript from JSON
- 1
Paste a sample JSON document into the editor.
- 2
Optionally rename the root type to match your domain.
- 3
Copy the generated interfaces into your codebase or a shared types package.
Keep going
Generate types in other languages
Produce Python, Java, Go, C#, Kotlin, Rust, or Swift types from the same JSON sample.
Generate a JSON Schema
Create a runtime contract you can validate against, in addition to compile-time types.
Mock data for these types
Generate matching fake data to build UI before the real backend exists.
Format the source first
Clean up the sample payload so the generated type names follow consistent casing.
Common JSON-to-TypeScript workflows
Generate interfaces from one real response and use them across every fetch call in your app.
Drop a sample webhook event in and get types your handler can import on day one.
Generate interfaces for structured AI output so the compiler flags missing or renamed fields.
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Frequently Asked Questions
Paste a JSON object and the tool analyzes the structure, data types, and nesting to generate TypeScript interfaces. Arrays are typed based on their contents, and nested objects get their own named interfaces.
The tool generates interfaces based on the sample data provided. If a field is present, it's marked as required. For optional fields, you'll need to add the ? modifier manually after reviewing the generated types.
Absolutely — that's one of the most popular uses. Copy a JSON API response, paste it in, and get TypeScript interfaces ready to use in your frontend code. This saves significant time when working with REST APIs.
Strings become string, numbers become number, booleans become boolean, null becomes null, arrays become typed arrays (e.g., string[]), and objects become named interfaces with all their properties.