JSON to TypeScript Interface Generator

What Is a JSON to TypeScript Converter?

A JSON to TypeScript converter analyzes JSON data structures and generates corresponding TypeScript interface definitions with inferred types. TypeScript is the strongly-typed superset of JavaScript used by millions of developers to catch type errors at compile time. Defining interfaces manually for complex API responses, database records, and configuration objects is tedious and error-prone.

This tool automates the process by examining each JSON property's value type and generating accurate TypeScript type annotations. Strings become string type, numbers become number, booleans become boolean, arrays are typed based on their contents, and nested objects generate separate named interfaces. The result is copy-paste-ready TypeScript code that you can drop directly into your project's type definition files. The entire analysis runs in your browser with 100% client-side processing, so your API response data never leaves your machine.

How to Generate TypeScript Interfaces from JSON

1. Paste your JSON data into the input panel. API responses, database records, or any valid JSON structure works.
2. Click Convert to analyze the JSON structure and generate TypeScript interfaces with properly inferred types for every property.
3. Review the generated interfaces in the output panel. Nested objects produce separate named interfaces, arrays include element types, and optional fields are identified.
4. Copy the TypeScript code and paste it directly into your .ts or .d.ts files. The generated interfaces are ready for use with zero modifications needed.

Why Use PinusX JSON to TypeScript Generator?

Frontend and full-stack developers working with REST APIs, GraphQL endpoints, and third-party services need TypeScript interfaces to maintain type safety throughout their applications. Manually writing interfaces for complex API responses with dozens of fields and nested objects takes significant time and introduces human error. PinusX generates accurate TypeScript interfaces instantly with 100% client-side processing — your API response data, including authentication tokens, user records, and business data, never leaves your browser. This matters especially when working with production API responses that contain real customer data.

Frequently Asked Questions

How does the tool infer TypeScript types?

The tool examines each JSON value's JavaScript type at runtime. Strings map to TypeScript 'string', numbers to 'number', booleans to 'boolean', null to 'null', arrays to typed arrays based on the first element, and nested objects generate separate interface definitions with PascalCase names.

Does it handle nested objects?

Yes. Each nested object generates a separate named TypeScript interface. For example, a JSON property 'address' containing an object generates a 'RootAddress' interface. This keeps the code clean and follows TypeScript best practices for interface decomposition.

How are JSON arrays typed?

Arrays are typed based on the first element. An array of strings becomes 'string[]', an array of numbers becomes 'number[]', and an array of objects generates a typed interface for the element type, resulting in something like 'UserItem[]'.

Can I use the output directly in my project?

Yes. The generated interfaces are valid TypeScript that can be pasted directly into .ts or .d.ts files. The code follows standard TypeScript conventions including PascalCase interface names and proper semicolons.

Is my API data safe?

Completely safe. The JSON to TypeScript conversion runs entirely in your browser. No API response data, user records, or business information is sent to any server. You can safely convert production API responses containing sensitive data.

Your data never leaves your browser. 100% client-side processing.