JSON → TypeScript Interface Generator
Paste JSON data and get TypeScript interfaces with proper types. Handles nested objects, arrays, optional fields, and union types.
JSON
TypeScript Interface
💡 Definition
TypeScript Interfaces
- TypeScript interfaces define the shape of objects with type annotations.
- Generating them from JSON sample data saves time and ensures type safety.
- This tool infers types from values: strings, numbers, booleans, arrays, and nested objects.
📖 How to use
Step by Step
- Paste a JSON object or array in the left panel
- TypeScript interfaces are generated instantly
- Nested objects become separate interfaces
- Arrays infer the type of their elements
🎯 Use cases
When to use
- Quick-start TypeScript projects from API responses
- Generating types for REST API payloads
- Converting JSON config files to typed interfaces
- Learning TypeScript type syntax
Frequently Asked Questions
How are types inferred?▾
String values → string, numbers → number, booleans → boolean, null → null, arrays → Type[], nested objects → separate interfaces. Mixed arrays use union types.
What about optional fields?▾
When generating from a single JSON object, all fields are marked as required. For arrays of objects, fields that don't appear in every item are marked optional (?) automatically.