JSON to TypeScript
Convert JSON data to TypeScript interfaces and types. Generate type-safe code from API responses automatically.
ℹ️ About JSON to TypeScript
JSON to TypeScript turns a sample payload into typed declarations, generating a named interface for the root object and a separate one for every nested object, with arrays typed from their elements. Objects inside an array are merged, so a key that only some elements carry becomes optional, and element interface names are singularized. Toggles switch between interface and type alias, add export, and mark properties optional or readonly. It suits the case where you have an example API response but no schema, and it runs entirely in your browser.
💡 Use Cases
📋 How to use
Paste a JSON object or array into the JSON box on the left, or click Sample to load an example payload; types are generated as you type.
Set Root Type Name to whatever you want the top-level type called, such as User or ApiResponse.
Tick interface to emit interface declarations, or untick it to get type aliases instead.
Use the Optional props, readonly and export checkboxes to add question marks, readonly modifiers and export keywords to the generated properties.
Read the TypeScript panel on the right, where nested objects are lifted out into their own named types.
Click Copy to put the finished definitions on your clipboard and paste them straight into your .ts file.
💎 Pro Tips
- Paste your content directly — the JSON To Typescript detects common input patterns and applies sensible defaults automatically.
- Use keyboard shortcuts (Ctrl/Cmd+A to select all, Ctrl/Cmd+C to copy) to speed up your workflow inside the JSON To Typescript.
- For very large inputs, break them into chunks — most browser tabs can handle megabytes of text, but parsing huge payloads may freeze the UI briefly.
- The JSON To Typescript does not log or store your input. If you need history, copy important outputs to a local file or note app.
- Combine the JSON To Typescript with other tools on this site (formatters, converters, encoders) to build complete data pipelines without leaving your browser.
❓ Frequently Asked Questions
Yes, fully free with no signup, no API key, no watermarks, and no usage limits.
No. The JSON To Typescript runs entirely client-side in your browser. Your input never touches our servers.
There is no hard limit, but expect slowdowns on inputs larger than a few megabytes, depending on your device's memory.
Yes. Outputs generated with the JSON To Typescript are yours to use freely in any personal or commercial project.
Most of the logic runs in client-side JavaScript, so after the initial load you can often keep working without a network connection.
None. Because the JSON To Typescript runs in your browser, you can process as many inputs as your hardware allows without API keys or throttling.