Input example
{
"id": 101,
"name": "Asha",
"active": true,
"profile": {
"email": "asha@example.com"
}
}TypeScript developer tool
JSON to TypeScript Interface Generator Online
Paste sample JSON and generate TypeScript interfaces for API responses, frontend models, typed data contracts, and documentation.
Generate interfacesBrowser tool
Create TypeScript interfaces from JSON
The input is processed locally in your browser. Review optional fields and API rules before using the generated type in production.
Paste or upload JSON, then generate TypeScript interfaces.
Why generate TypeScript interfaces from JSON?
When you receive a JSON response from an API, webhook, export, or internal service, you often need TypeScript types before using that data in a frontend app, Node.js project, SDK, or documentation page. Writing interfaces by hand is slow, and it is easy to miss nested fields or array shapes. This JSON to TypeScript interface generator creates a starter type definition from a real JSON example so you can move faster.
The tool detects common JavaScript and JSON value types such as strings, numbers, booleans, null values, arrays, and nested objects. It also quotes property names that are not valid TypeScript identifiers. The output is meant to be copied into a codebase, reviewed, renamed, and improved with optional fields, union types, enums, and stricter business rules where needed.
Example
JSON to TypeScript example
This shows how a small API response can become a starter TypeScript interface.
Output example
export interface Profile {
email: string;
}
export interface GeneratedRoot {
id: number;
name: string;
active: boolean;
profile: Profile;
}When to use this tool
Use this generator when creating TypeScript models for API responses, admin dashboards, React components, Next.js data loaders, Node.js services, SDK examples, test fixtures, or typed documentation. It is helpful when you have real JSON but no official TypeScript type yet, or when a third-party response is poorly documented and you need a quick first draft.
The generated interface should not be treated as the final truth for your application. A single JSON sample cannot know whether a field is optional, whether a string should be a date, whether a number should be limited, or whether an array can contain several item shapes. Use the output as a starting point, then refine it based on API documentation and real examples.
Common mistakes
Review before copying into a codebase
Optional fields
If a field is missing from some responses, add a question mark such as email?: string after generating the interface.
Date strings
JSON dates are usually strings. Decide whether your code should keep them as strings or transform them into Date objects after parsing.
Arrays from one example
An array with one item may not show every possible item shape. Test with several examples before relying on the generated array type.
Enums and fixed values
A value like "active" is detected as string. Replace it with a union such as "active" | "paused" when the API has known values.
Privacy and local browser processing
This JSON to TypeScript generator is designed to run in your browser with client-side JavaScript. You can paste JSON, generate an interface, copy the output, download it, or create a share link for safe examples. Share links can include the content you entered, so only use them when the JSON is appropriate to show to another person.
Do not paste passwords, API keys, private tokens, customer records, payment data, confidential production payloads, or internal identifiers into any online tool unless your own policy allows it. For sensitive systems, create a small fake JSON sample with the same structure and harmless placeholder values.
FAQ
JSON to TypeScript Generator FAQ
What does this JSON to TypeScript tool do?
It reads valid JSON and creates TypeScript interfaces or root types based on the detected fields, nested objects, arrays, strings, numbers, booleans, and null values.
Can it generate perfect production types?
No. It generates a helpful first draft. Review optional fields, enums, date strings, nullable values, and API-specific rules before using the result in production.
Can I generate TypeScript from a JSON array?
Yes. If you paste an array, the tool infers an item type and creates a root array type.
Should I use this with the JSON Schema generator?
Yes. TypeScript interfaces are useful for code, while JSON Schema is useful for validation and documentation. Many API workflows benefit from both.