🔷

JSON to TypeScript Types Generator

Paste any JSON and instantly get TypeScript interfaces, type aliases, or Zod schemas. Handles nested objects, arrays, null values, and optional fields — 100% in-browser.

100% in-browserInterface · Type · ZodNested objectsNo signup

Samples:

data.json

types.ts

TypeScript types will appear here

Paste JSON on the left or load a sample

Output

Root name

Optional nullsSemicolonsExport all

Stop Writing TypeScript Types by Hand

Every time you add a new API endpoint or change a response shape, you update the TypeScript interfaces by hand — copy the JSON from the browser network tab, mentally map each field to a type, handle nested objects, figure out what is optional, and hope you did not miss anything. It is the most repetitive part of front-end development.

Paste any JSON — user objects, API responses, config files, database records — and get immediately correct interface, type, or Zod definitions. Nested objects become separate named interfaces. Arrays are correctly typed as string[], User[], or union types.null values become optional fields. Copy and paste the result into your codebase.

How it works

Paste JSON, Get Types in One Step

Paste your JSON

Paste any valid JSON object or array into the left editor. Use a sample preset to try it instantly.

Pick your output format

Choose interface (default), type alias, or Zod schema. Set the root interface name and toggle options like "export all" and "optional nulls".

Copy and use

The TypeScript output updates in real-time. Click Copy to grab it and paste it straight into your project.

Use cases

When Developers Use a JSON to TypeScript Generator

🔗

API Integration

Copy a JSON response from your browser DevTools network tab and instantly get the TypeScript interface for the API data.

🗃️

Database Schema Typing

Take a sample record from your database and generate TypeScript types for your ORM or data access layer.

📦

Third-party SDK Types

When a library ships without TypeScript types, paste its JSON payload format to generate your own type declarations.

🤖

AI Response Typing

Generate TypeScript interfaces for ChatGPT, Claude, or Gemini API JSON responses before integrating them into your app.

⚙️

Config File Types

Create typed configuration objects for app settings, feature flags, or environment variable schemas.

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Test Fixture Types

Generate types from test fixture JSON files to ensure your mock data matches your production interface shapes.

FAQ

Frequently Asked Questions

1How do I convert JSON to a TypeScript interface?

Paste your JSON in the left editor — TypeScript interfaces appear instantly on the right. The tool infers all types including nested objects, arrays, strings, numbers, and booleans.

2What is the difference between interface and type in TypeScript?

Both can describe an object shape. Interfaces support declaration merging and are preferred for object shapes. Type aliases are more flexible — they can represent unions, intersections, and primitives. For plain JSON, both work identically.

3Can this tool generate Zod schemas?

Yes. Switch to "Zod" in the output options to get a z.object() schema with correct z.string(), z.number(), z.boolean(), z.null(), and z.array() types.

4How are nested objects handled?

Each nested object becomes its own named interface, named after the parent key in PascalCase. The parent interface references the child by name.

Learn more

Developer Guides

📖TypeScript Best Practices 📖Typed API Clients in TypeScript 📖Zod Schema Validation Guide 📖JSON Schema vs TypeScript Types

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