How to Convert JSON to TypeScript Types

You've got a JSON response from an API and you want TypeScript interfaces that match it — so your editor autocompletes fields and the compiler catches typos. Writing those types by hand from a big nested payload is slow and easy to get wrong. A JSON-to-TypeScript generator reads the shape of your data and produces the interfaces for you.

Why generate types from JSON

• Autocomplete — your editor knows every field and its type.
• Compile-time safety — mistyped or missing properties fail the build, not production.
• Speed — turn a 200-line API response into types in a second.
• Accuracy — the types exactly match the real data, nesting and all.

Step-by-step: convert with ToolsGravity

1. Open the JSON to TypeScript tool and paste a JSON sample (a real API response works best).
2. Get TypeScript interfaces matching the structure, including nested objects and arrays.
3. Copy the types into your project and use them to type your fetch results.

What it looks like

This JSON:

{
  "id": 1,
  "name": "Ada",
  "roles": ["admin", "editor"]
}

becomes this TypeScript:

interface Root {
  id: number;
  name: string;
  roles: string[];
}

Tips

• Use a representative sample. The generator infers types from the data it sees — include an example with all fields populated so nothing is missed.
• Check optional fields. If a property is sometimes absent, mark it optional (?) after generating.
• Validate first. Make sure your JSON is valid before converting — a quick pass through a JSON formatter catches syntax errors.

Summary

Generating TypeScript types from JSON gives you autocomplete and compile-time safety in seconds, with types that exactly match your API. Paste a full sample, review optional fields, and use the ToolsGravity JSON to TypeScript tool right in your browser.