Yes, the tool operates entirely client-side. Your JSON is never uploaded to any server.

JSON to TypeScript Interface - Free Online Converter

Q: Should I use Interface or Type?

Interfaces are generally preferred for object shapes as they can be extended. Types are useful for unions. This tool supports both.

Q: How does it handle arrays?

It detects the type of the items inside the array (e.g., objects or primitives) and generates the appropriate array syntax, like MyObject[].

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JSON to TypeScript Converter

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About the JSON to TypeScript Converter

TypeScript is essential for modern web development, providing type safety and better developer tooling. However, manually writing interfaces for large JSON responses from APIs can be tedious and error-prone. This JSON to TypeScript Converter automates that process completely.

Simply paste your raw JSON data into the tool, and it will instantly parse the structure to generate clean, valid TypeScript interfaces or type aliases. It is smart enough to handle nested objects (creating separate sub-interfaces for clarity) and arrays. It detects primitive types like string, number, and boolean, and assigns any to null values.

This tool runs entirely in your browser. Your JSON data is never sent to any server, ensuring that sensitive API responses or configuration files remain private.

Features

Instant Conversion: See the TypeScript output update in real-time as you type or paste JSON.
Nested Object Support: Automatically extracts nested objects into their own named interfaces.
Custom Root Name: Define the name of the main interface to match your coding standards.
Interface vs Type: Toggle between generating interface definitions or type aliases.
Syntax Highlighting: Easy-to-read editors for both input and output.

Frequently Asked Questions

Should I use Interface or Type?

In TypeScript, both are very similar. generally, interface is preferred for defining the shape of objects and can be extended (merged). type aliases are more flexible and can define unions or primitives. For API responses, either works well, but this tool defaults to interface as it is the convention for object shapes.

How does it handle arrays?

The tool analyzes the first element of an array to determine the type. If the array contains objects, it generates an interface for that object and sets the property type to ObjectName[].

Is my data secure?

Yes. The conversion logic is written in JavaScript and executes locally on your device. We do not store or view your JSON data.