How does nested object type generation work?

When an object property contains another nested object, the generator creates a separate PascalCase interface (e.g., UserAddress) and references it in the parent interface for modular code.

Can I generate type aliases instead of interfaces?

Yes. Toggle between "interface" and "type" output formats depending on your project coding standards.

Does it support arrays with multiple object shapes?

Yes. If an array contains objects with varying fields, the converter analyzes all elements to merge common and optional properties into an accurate type.

Can I add readonly modifiers to all properties?

Yes. Enable the "Readonly properties" toggle to prefix every generated property with the TypeScript readonly keyword.

Is my JSON payload kept confidential?

Yes. All parsing and TypeScript type generation occurs purely within your browser using JavaScript. No payload data is ever transmitted or logged.

JSON to TypeScript Converter

Convert JSON objects and API responses into clean TypeScript interfaces and types.

100% free
Private in browser
No signup
No watermarks

JSON Payload

TypeScript Definitions

3 types generated

export interface Address {
  street: string;
  city: string;
  country: string;
  pincode: string;
}

export interface Metadata {
  lastLogin: string;
  loginCount: number;
}

export interface UserProfile {
  id: number;
  name: string;
  email: string;
  isActive: boolean;
  roles: string[];
  address: Address;
  metadata: Metadata;
}

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About JSON to TypeScript Converter

JSON to TypeScript Converter on TheToolss turns JSON objects, array payloads, and REST API responses into strongly typed TypeScript interfaces or type aliases. It recursively traverses nested objects to create clean sub-interfaces, infers union types from array elements, and supports optional properties and readonly modifiers. All type generation runs client-side in your browser.

How to use JSON to TypeScript Converter

Paste your JSON payload or API response into the input box.
Configure the root interface name, output style (interface vs. type), and modifiers.
View generated TypeScript types and click Copy to clipboard.

Key features

Generates clean TypeScript interfaces or type definitions from any JSON
Automatically extracts nested objects into reusable sub-interfaces
Handles primitive arrays, mixed object arrays, and nullable values
Configurable readonly modifiers and optional property flags
100% private and client-side processing without uploading payloads

Frequently asked questions

How does nested object type generation work?: When an object property contains another nested object, the generator creates a separate PascalCase interface (e.g., UserAddress) and references it in the parent interface for modular code.
Can I generate type aliases instead of interfaces?: Yes. Toggle between "interface" and "type" output formats depending on your project coding standards.
Does it support arrays with multiple object shapes?: Yes. If an array contains objects with varying fields, the converter analyzes all elements to merge common and optional properties into an accurate type.
Can I add readonly modifiers to all properties?: Yes. Enable the "Readonly properties" toggle to prefix every generated property with the TypeScript readonly keyword.
Is my JSON payload kept confidential?: Yes. All parsing and TypeScript type generation occurs purely within your browser using JavaScript. No payload data is ever transmitted or logged.

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