TypeScript Interface Generator is a free, browser-based tool built for developers who need typed models from an API response without writing them by hand.
Paste any JSON object or array and get matching interface declarations, with nested objects broken out automatically.
How to use the TypeScript Interface Generator
- Paste a JSON object or array into the input box.
- Optionally set a name for the root interface.
- TypeScript interfaces are generated instantly, including nested types.
- Copy the result into a .ts or .d.ts file in your project.
Why use FreeToolsNets's TypeScript Interface Generator?
- 100% free, with no usage limits and no account required.
- Everything runs locally in your browser — nothing you type is uploaded or stored on a server.
- Works on desktop, tablet and mobile in any modern browser.
- No installation, no plugins, and no ads blocking the tool itself.
- Part of FreeToolsNets's Developer & Data Tools collection.
Frequently asked questions
Does it handle arrays of objects?
Yes — arrays of objects generate a separate interface for the item shape.
What happens with null values?
Null values are typed as null; widen them manually to a union type if needed.
Is this tool free to use?
Yes, completely free on FreeToolsNets, with no sign-up and no limits.
Is my data sent to a server?
No. Everything runs locally in your browser using JavaScript — nothing you enter is uploaded anywhere.
Does it work on mobile?
Yes, the widget is fully responsive and works on phones, tablets and desktops.