JSON to TypeScript Interface Generator Online Free

Input

{
  "id": 101,
  "name": "DevToolPad User",
  "email": "hello@example.com",
  "isActive": true,
  "tags": ["frontend", "typescript"],
  "address": {
    "city": "Bengaluru",
    "country": "India"
  },
  "projects": [
    {
      "name": "DevToolPad",
      "stars": 42
    },
    {
      "name": "Tooling Hub"
    }
  ]
}

Input chars: 322Input lines: 20Nested object and array aware

Output

interface RootObject {
  id: number;
  name: string;
  email: string;
  isActive: boolean;
  tags: string[];
  address: {
    city: string;
    country: string;
  };
  projects: {
    name: string;
    stars?: number;
  }[];
}

Output chars: 227Output lines: 16Ready for TS projects

About This Tool

JSON to TypeScript Interface Generator converts JSON data into clean TypeScript interfaces and types in real time, directly in your browser for free. When consuming REST APIs or working with JSON configurations, writing TypeScript interfaces by hand is repetitive and error-prone. This tool infers the type of every JSON field, handles deeply nested objects by generating child interfaces, converts arrays to correctly typed array types, and marks fields that differ across objects as optional. The output is immediately usable in React, Vue, Angular, Node.js, and any TypeScript project. No libraries or sign-up required.

How to Convert JSON to TypeScript Interfaces

Paste your JSON payload or API response into the input editor.
Review the generated TypeScript interfaces on the right.
Copy the output or download it for your project.
Rename interfaces to match your domain model (e.g., User, Product).
Import the interfaces into your TypeScript files.

Features

Handles nested objects and arrays recursively.
Marks optional fields when object shape varies in arrays.
Generates clean interface declarations ready to import.
Works fully client-side for privacy and speed.

Common Use Cases

Type-safe REST API response modeling in TypeScript
Adding types to React component props from JSON payloads
Node.js API contract generation from JSON schemas
Vue or Angular service type safety from API responses
Auto-typed configuration objects for TypeScript projects

Frequently Asked Questions

How do I convert JSON to TypeScript interface online for free?

Paste your JSON into the input editor. The tool generates TypeScript interfaces for every object structure in your JSON, instantly and for free, with no sign-up.

Does the tool handle nested JSON objects?

Yes. Nested JSON objects produce child TypeScript interfaces. Each level of nesting becomes a separate named interface.

How are JSON arrays converted to TypeScript types?

JSON arrays become typed array fields using the element type, e.g. `items: Item[]`. If the array contains objects, a corresponding child interface is generated.

Does this tool generate TypeScript types or interfaces?

The tool generates TypeScript `interface` declarations, which are ideal for describing object shapes in APIs and components. You can rename them to `type` aliases if preferred.

Can I use the generated interfaces in React or Vue?

Yes. The generated interfaces are pure TypeScript and can be imported directly into React components, Vue composables, Angular services, or any TypeScript module.

Is my JSON data safe when using this tool?

Yes. The conversion runs entirely in your browser. Your JSON data is never sent to any external server.

What JSON to TypeScript type mappings are used?

String values become `string`, numbers become `number`, booleans become `boolean`, arrays become `T[]`, null values become `null | T`, and nested objects become child interfaces.