Generating TypeScript interfaces from JSON by hand is tedious and error-prone - a JSON to TypeScript generator does it in seconds, handling nested objects, arrays, and optional fields automatically.
What is JSON to TypeScript Conversion?
When building TypeScript applications that consume REST APIs, you need type definitions that match the API response shape. Writing these interfaces by hand requires reading through the JSON, figuring out every property name and type, and handling nested structures correctly.
A JSON to TypeScript tool reads the structure of a JSON object and generates matching TypeScript interface declarations - giving you type safety, autocomplete, and documentation all at once.
How to Use the JSON to TypeScript Generator
- Open the JSON to TypeScript tool on UtilWave.
- Paste a JSON object (not an array at the top level - wrap arrays if needed).
- The tool immediately generates TypeScript interfaces on the right panel.
- Nested objects produce their own named interfaces.
- Arrays of objects produce typed arrays (
InterfaceName[]). - Click Copy to paste the interfaces directly into your TypeScript file.
Common Use Cases
Typing API responses - Copy a response body from your browser's DevTools or Postman, paste it in, and have the types ready in seconds.
Third-party webhook payloads - Stripe, GitHub, and Slack webhooks deliver complex nested JSON. Convert the example payload from their docs into types you can use immediately.
Database query results - When using raw queries (not an ORM), convert the result shape to an interface so TypeScript can enforce its structure.
Configuration objects - Turn a JSON config file into a typed config interface to prevent typos and catch missing keys at compile time.
Example
Input JSON:
{
"id": 1,
"name": "Alice",
"address": { "city": "New York", "zip": "10001" },
"tags": ["admin", "user"]
}
Generated TypeScript:
interface Address {
city: string;
zip: string;
}
interface Root {
id: number;
name: string;
address: Address;
tags: string[];
}
FAQ
Does it handle arrays of objects? Yes. An array of objects generates a typed array with a named interface for the element type.
What happens with mixed-type arrays?
If an array contains both strings and numbers, the type is inferred as (string | number)[].
Are nullable fields handled?
Properties with null values are typed as T | null. If you want all optional fields, you can manually add ? after generation.
Can I rename the root interface?
The root interface is named Root by default. You can rename it in your code after copying.
Generate TypeScript interfaces instantly with the JSON to TypeScript tool.