Free · No sign-up · Runs in browser
JSON → TypeScript
Interface Generator
Paste your JSON array or object and get accurate, ready-to-use TypeScript interfaces with proper types, optional fields, and nested structures. Runs 100% in your browser — nothing leaves your device.
JSON Input
TypeScript Output
// Your TypeScript interfaces will appear here…
Smart type inference
Strings, numbers, booleans, Date (ISO), arrays, nested objects and JSONB — all detected and typed accurately.
Optional fields
When converting arrays, keys missing or null in any row become optional (?) in the generated interface.
Bidirectional
Convert JSON → TypeScript interfaces, or paste existing interfaces to get a JSON skeleton back.