CSV to JSON Converter
Convert Comma-Separated Values (CSV) to JavaScript Object Notation (JSON) online for free. Runs 100% in your browser. Files never leave your device. No signup, no watermarks, no limits.
Drag & drop files or Browse
Processed on your device. Nothing is uploaded
Automate this. An open tab can convert whole folders via the Local API — still zero uploads.
Local API →How to use CSV to JSON Converter
- 01Add files
Choose files or drop them here
- 02Settings
Settings · Runs on your device
- 03Download
Processed on your device. Nothing is uploaded
What is a CSV (Comma-Separated Values) file?
CSV is the simplest spreadsheet interchange format. One row per line, values separated by commas. Every spreadsheet app and programming language can read it.
- Developed by
- Unknown
- Initial release
- 1972
What is a JSON (JavaScript Object Notation) file?
JSON is the dominant lightweight data-interchange format on the web. Human-readable key/value structures understood by every programming language and API.
- Developed by
- Douglas Crockford
- Initial release
- 2001
Frequently asked questions
How do I convert CSV to JSON?
Click “Choose Files” or drag your CSV file onto the page, optionally adjust the settings, then hit Convert. Your JSON file downloads straight from your browser. Nothing is uploaded anywhere.
Is this CSV to JSON converter free?
Yes, completely free with no hidden limits, watermarks or signup. Because all processing happens on your own device, there are no server costs to pass on to you.
Are my files uploaded to a server?
No. The conversion engine runs entirely in your web browser using WebAssembly. Your files never leave your device. You can even disconnect from the internet after the page loads and keep converting.
Is there a file size limit?
We impose no fixed limit. The practical ceiling is your device's free memory, since processing happens locally. Most conversions work comfortably with files up to a few hundred megabytes, and image or document conversions handle much more.
Does it work on my phone?
Yes. The converter runs in any modern browser on Windows, macOS, Linux, Android and iOS. No app installation is required.