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JSON to TypeScript – Generate TypeScript Interfaces from JSON

Convert JSON to TypeScript interfaces instantly with automatic type inference, nested object support, and optional fields detection.

🟢 Runs locally · no uploads

JSON to TypeScript Converter

Convert JSON data to TypeScript interfaces

lightbulbPopular Use Cases

api
API Response Types

Convert REST/GraphQL responses to TypeScript interfaces

settings
Config Files

Generate types for JSON configuration files

edit_note
Form Data

Type form submissions and validation schemas

storage
Database Results

Type query results from databases

JSON Input
TypeScript Output
code

TypeScript interfaces will appear here

Characters: 0Lines: 0Interfaces: 0

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› About this tool · FAQ

Stop manually writing TypeScript interfaces for API responses! Convert JSON to TypeScript interfaces instantly with support for nested objects, optional properties, and union types. Completely free, works offline in your browser, no file uploads.

How do I convert JSON to TypeScript?

Paste your JSON data into the converter, configure interface options (optional properties, union types, camelCase), and click Generate. The tool creates TypeScript interfaces instantly with proper type definitions for all properties, nested objects, and arrays.

What is the best JSON to TypeScript converter?

This free JSON to TypeScript interface generator handles nested objects, arrays, optional properties, and union types automatically. It works offline in your browser with no data uploads, making it perfect for converting API responses to TypeScript types safely.

Is this JSON to TypeScript tool free?

Yes, completely free with no limits, no signup required, and no watermarks. Convert unlimited JSON data to TypeScript interfaces with full feature access including nested object handling, optional properties, and custom formatting.

How does it handle arrays with different item types?

With "Infer Array Types" enabled, it creates union types like (string | number)[] for mixed arrays. It can also generate separate interfaces for object arrays with proper type definitions.

What about optional properties?

Enable "Optional Properties" to mark properties with null/undefined values as optional (property?: type). This makes interfaces more flexible for incomplete data from API responses.

Can it handle deeply nested objects?

Yes, it automatically generates separate interfaces for nested objects and references them properly. Each nesting level gets its own interface definition with full type safety.

How does it handle invalid property names?

Properties with spaces or special characters are automatically quoted ("property name": type). Enable camelCase conversion for cleaner property names that follow TypeScript conventions.

Is my JSON data uploaded to servers?

No, all JSON to TypeScript conversion happens locally in your browser. Your data never leaves your computer, ensuring complete privacy for sensitive API responses and proprietary data structures.