JSON to TypeScript Interface Generator
Paste any JSON object and instantly generate clean TypeScript interfaces with nested types, arrays, and optional fields.
JSON Input
Tip: Press Ctrl+Enter to generate
TypeScript Output
About JSON to TypeScript Generator
Stop writing TypeScript interfaces by hand. Paste any JSON — from an API response, a config file, or a database record — and get fully typed TypeScript interfaces in one click. Nested objects, arrays, nullable fields, and union types are all handled automatically.
How It Works
- Paste your JSON object or array into the left panel
- Set a root interface name (default: Root)
- Click Generate TypeScript or press Ctrl+Enter
- Copy or download the .ts file
Key Features
- Generates TypeScript interfaces from any valid JSON
- Nested objects produce separate named interfaces
- Arrays with object items generate typed item interfaces
- Null values are marked as optional with union null type
- Download result as a ready-to-use .ts file
- 100% browser-based — your data never leaves your device
Frequently Asked Questions
- How do I generate TypeScript interfaces from a JSON API response?
- Copy the JSON response from your browser's DevTools network tab (or from Postman), paste it into the left panel, give the root interface a name that matches your data model, then click Generate TypeScript. The tool creates one interface per nested object automatically.
- Does it handle nested objects and arrays?
- Yes. Each nested object becomes its own named interface. Arrays of objects generate a typed item interface (e.g. RootItem[]). Arrays of primitives produce string[], number[], or boolean[]. Mixed arrays produce union types like (string | number)[].
- What happens to null values in the JSON?
- Fields with null values are typed as string | null and marked optional with ?. This is the safest assumption since null usually means the field can be absent or empty. You can always tighten the type manually after generating.
- Is my JSON data safe to paste here?
- Yes — all processing happens entirely in your browser using JavaScript. Your JSON is never sent to any server. You can safely paste API keys, tokens, database records, or any sensitive data without privacy concerns.