CodeItBro

JSON to TypeScript Converter

Convert JSON objects to TypeScript interfaces or type definitions. Generate type-safe code instantly.

TypeScript interfaces will appear here

Pro Tips

  • • Use meaningful root names that describe your data (e.g., UserResponse, Product)
  • • Enable optional properties if some fields might be missing in your API responses
  • • Nested objects are automatically extracted into separate interfaces for cleaner code
  • • Array items are typed based on the first element's structure

Generate TypeScript Types from JSON

Stop manually writing TypeScript interfaces for your API responses. Paste your JSON and get production-ready TypeScript types instantly. Perfect for frontend developers working with REST APIs, GraphQL, or any JSON data source.

TypeScript Generation

Why Use This Tool?

Save Time

Generate interfaces in seconds instead of manually typing them for complex nested objects.

Nested Support

Automatically handles nested objects and arrays with proper type generation.

Configurable

Choose between interface and type, add exports, and make properties optional.

100% Private

All conversion happens in your browser. Your data never leaves your device.

How this JSON to TypeScript Converter works

This converter analyzes JSON structure and generates corresponding TypeScript interface definitions through recursive type inference. The algorithm traverses the JSON object tree, determining appropriate TypeScript types for each value: string, number, boolean, null, arrays, and nested objects. Nested objects are extracted into separate named interfaces for cleaner, more maintainable type definitions.

The generator handles complex scenarios including arrays of objects (typed by analyzing the first element), mixed-type arrays (union types), and deeply nested structures. Configuration options let you choose between interface and type alias syntax, add optional property markers for nullable fields, control export keywords, and customize the root interface name to match your codebase conventions.

Property names with special characters are automatically quoted to ensure valid TypeScript syntax. Array items get dedicated interfaces with "Item" suffix naming convention. All conversion happens client-side in your browser, making it safe for converting API responses containing sensitive data. This tool significantly accelerates frontend development by eliminating manual type definition writing when integrating with REST APIs or other JSON data sources.

How to Use

1

Paste JSON

Enter your JSON data in the input editor.

2

Configure

Set options like interface name, optional properties, and export style.

3

Generate

Click Convert to generate TypeScript interfaces.

Example Usage

Converting a simple JSON object:

Input
{"name": "John", "age": 30}
Output
export interface Root { name: string; age: number; }

Frequently Asked Questions

What is this tool for?
It converts JSON data into TypeScript interfaces or types, helping you add type safety to your TypeScript projects.
Does it handle nested objects?
Yes! The converter automatically creates separate interfaces for nested objects and arrays of objects.
What's the difference between interface and type?
Interfaces are extendable and preferred for object shapes. Types are more flexible but can't be extended. Choose based on your project's needs.
Is my data safe?
Yes, all processing happens in your browser. No data is sent to any server.

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The JSON to TypeScript Converter is maintained by CodeItBro. We aim to provide the best free developer tools on the web. If you have feedback or suggestions, please visit our contact page.