Free Online JSON to TypeScript Interface Converter
Features
Instant JSON to TypeScript types
Paste any JSON and get the matching TypeScript interfaces and type aliases in real time — no clicks, no build step, no setup.
Nested objects and arrays
Deeply nested objects, arrays of objects and primitive arrays are all converted into correctly structured, composable interfaces.
Merged array item interfaces
Array items that share the same shape are combined into a single interface, so your generated types stay clean and DRY instead of duplicated.
Live preview with sample data
A ready-made example loads on start so you can see how it works, then replace it with your own payload and watch the types update as you type.
Runs locally in your browser
Conversion happens on-device with the json-to-ts library, so your JSON never leaves your machine and there is no server round trip.
Frequently asked questions
How do I convert JSON to a TypeScript interface?
Paste your JSON into the editor on the left. The matching TypeScript interface or type is generated instantly on the right — just copy it into your project.
Is this JSON to TS converter free to use online?
Yes. It is a free online converter with no registration and no usage limits, and it works entirely in your browser.
Can it handle nested objects and arrays?
Yes. Nested objects, arrays of objects and primitive arrays are all converted into properly structured interfaces and type aliases.
What happens when several array items share the same fields?
Their shapes are merged into a single interface, so an array of similar objects becomes one reusable typed array instead of duplicated definitions.
Is my JSON sent to a server?
No. The conversion runs locally in your browser using the json-to-ts library, so whatever you paste stays on your device.
