JSON to TypeScript Converter

Convert JSON to TypeScript interfaces or type aliases with nested types, union types for mixed arrays, and optional or readonly fields.

JSON input382 chars

TypeScript output333 chars

export interface Projects {
  id: number;
  name: string;
  tags: string[];
}

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

export interface Root {
  avatar: null;
  email: string;
  id: number;
  isActive: boolean;
  metadata: Metadata;
  name: string;
  permissions: string[];
  projects: Projects[];
}

Features

Smart type inference for primitives

Nested object extraction

Array type detection with union types

Null handling and optional properties

Special character key escaping

PascalCase naming for nested types

Updated October 2, 2026. Provided as is. Check the output before you rely on it in production.

How to use JSON to TypeScript Converter

1

Paste valid JSON

Input a JSON object or array. The tool automatically infers TypeScript types from the structure: strings become `string`, numbers become `number`, objects become interfaces, arrays with consistent types become `Type[]`.
2

Configure generation options

Name the root interface, switch between `interface` and `type`, and toggle `readonly` properties, optional fields, `unknown` instead of `any`, and the `export` keyword.
3

Handle nested structures

Complex JSON with nested objects generates nested TypeScript interfaces. Each nested object gets its own interface, making the types reusable and easier to refactor.
4

Copy and integrate

Copy the generated TypeScript definitions into your project. Add them to a types file or at the top of your service file. Use the generated types for API responses, function parameters, and state management.

Questions and answers

What is JSON to TypeScript Converter?

TypeScript interfaces describe an object's shape so the compiler can check property names and types. This converter infers interfaces or type aliases from sample JSON, with a named type per nested object, union types for mixed arrays, and options for optional and readonly fields, unknown instead of any, and export.

Does JSON to TypeScript Converter store or send my data?

No. All processing happens entirely in your browser. Your JSON data never leaves your device — nothing is sent to any server.

Does JSON to TypeScript Converter handle nested objects?

Yes. It creates separate named interfaces for nested objects and types arrays of objects as one interface merging every key seen across the elements. Arrays mixing primitive types become a union such as (string | number)[].

Use it as an API

JSON to TypeScript Converter is also callable as a free HTTP JSON API at https://aidevhub.io/api/json-to-typescript/ — GET with query parameters or POST with a JSON body, no authentication, CORS enabled, fair use (abusive traffic is throttled at the edge; there is no per-request quota header). Responses return { ok, tool, result, meta }.

curl -s -X POST https://aidevhub.io/api/json-to-typescript/ \
  -H "Content-Type: application/json" \
  -d '{"json":"{\"id\":1,\"name\":\"Alice\"}","root_name":"User"}'

Machine-readable contract: /api/tool/json-to-typescript.json All API endpoints: /agents/ LLM site index: /llms.txt

For AI agents: how to call this tool

Machine-readable contract, endpoints and examples. Humans can ignore this section.

Best Path For Builders

Dedicated API endpoint

Deterministic outputs, machine-safe contracts, and production-ready examples.

Dedicated API

https://aidevhub.io/api/json-to-typescript/

OpenAPI: https://aidevhub.io/api/openapi.yaml

GET /api/json-to-typescript/ GET json-to-typescript

POST /api/json-to-typescript/ POST json-to-typescript

JSON to TypeScript Converter