JSON to TypeScript Interface
This tool instantly converts any JSON object into well-structured TypeScript interfaces by recursively inspecting each key-value pair and mapping JSON data types to their TypeScript equivalents — strings, numbers, booleans, null, typed arrays, and nested interface definitions. Deeply nested objects automatically generate separate, named interfaces so your code stays readable and maintainable.
Type inference works entirely in your browser without sending data to any server, making it safe for use with sensitive payloads. Paste the raw JSON response from any REST API, configuration file, or database record, give the root interface a meaningful name, and receive clean, copy-ready TypeScript code in milliseconds.
How it works
For each JSON value: string → string, number → number, boolean → boolean, null → null, [] → unknown[] (or T[] when all items share type T), {} → a named interface. Nested objects recurse depth-first, emitting child interfaces before their parent so declarations are always in dependency order.
Use cases
- Typing REST API responses to enable IntelliSense and catch runtime shape mismatches
- Bootstrapping TypeScript models from JSON database documents or schema samples
- Converting third-party webhook payloads into typed contracts for safer integration
- Speeding up onboarding by auto-generating interfaces from example JSON fixtures
- Auditing deeply nested configuration files to understand their full type structure