JSON to TypeScript - Free Online Interface Generator
Generate TypeScript interfaces from JSON data instantly. Perfect for API response types and data models.
Generated TypeScript will appear here...
JSON ↔ TypeScript Converter
Generate TypeScript interfaces or type aliases from JSON data. Perfect for defining API response types, configuration schemas, and data models.
- Switch between Interface and Type Alias output
- Recursively generates types for nested objects
- Detects arrays and generates array element types
- Handles null values with optional fields (? mark)
- Customizable root type name
- All processing happens in your browser
About JSON ↔ TypeScript
Generate TypeScript interfaces from JSON data instantly. Perfect for API response types and data models. JSON ↔ TypeScript is a free online tool by NeXiilo — no sign-up required, and everything runs privately in your browser.
Whether you use it daily for work or occasionally for a quick task, JSON ↔ TypeScript gives you fast, accurate results without uploading your data anywhere.
How to Use JSON ↔ TypeScript
- Open the JSON ↔ TypeScript above — paste or enter your input.
- Adjust any options to match what you need.
- Get instant results right in your browser.
- Copy or reuse the output wherever you need it.
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Frequently Asked Questions
What does JSON to TypeScript do?
It analyzes your JSON data and generates TypeScript interfaces that describe its structure. This is useful for defining API response types, configuration schemas, and data models.
How are nested objects handled?
Nested objects are recursively converted into their own interfaces. Each nested interface is named based on its parent interface and property name (e.g., RootObjectAddress).
How are arrays converted?
Arrays are converted to array types (T[]). If the array contains objects, a separate interface is generated for the array element type. Mixed-type arrays use union types.
How are null values handled?
Properties with null values are marked as optional using the ? modifier (e.g., profile?: null). This reflects that the property may or may not be present.
Can I customize the root interface name?
Yes, you can set a custom root interface name using the Root Name input field. The default is RootObject, and nested interfaces are named based on this root.