JSON to TypeScript Converter Online
Paste JSON and instantly generate TypeScript interfaces or type definitions.
What Is JSON to TypeScript Converter?
JSON to TypeScript Converter is a free online tool that analyzes a JSON object and generates the corresponding TypeScript interface or type definition. It handles nested objects, arrays, primitive types, and null values — saving you the time of writing type definitions by hand when working with API responses or configuration files.
How to Use JSON to TypeScript Converter
- Paste your JSON into the left panel, or click Load Sample to try an example.
- Set the root interface name (defaults to
Root). - The TypeScript interface appears instantly in the right panel.
- Click Copy to copy the result to clipboard.
Features
- Generates TypeScript interfaces for objects and type aliases for primitives/arrays
- Handles nested objects, arrays, and all primitive types
- Marks null fields as optional (?)
- Customizable root interface name
- Runs entirely in your browser — zero data uploaded
FAQ
What does JSON to TypeScript Converter do?
It analyzes your JSON structure and generates TypeScript interface or type definitions that match the shape of your data, including nested objects and arrays.
How are nullable fields handled?
Fields with null values are marked as optional (?) in the generated interface, since null typically indicates an optional or missing value.
Is my JSON data sent to a server?
No. All conversion happens entirely in your browser. Your data never leaves your device.