Free CSV to JSON Converter Online
Convert CSV to JSON instantly — upload a file or paste data, copy the result in one click.
CSV Input
Drop CSV here or click to upload
Options
JSON Output
// JSON output will appear here after conversion
How it works
Upload or paste CSV
Drop a CSV file onto the upload area or paste raw CSV text into the input panel on the left.
Choose output format
Select array of objects (default), array of arrays, and whether to auto-detect numbers. Adjust to match your API needs.
Review the JSON
The JSON output appears instantly in the right panel. Each CSV row becomes an object with header keys.
Copy or download
Click Copy to copy JSON to clipboard, or Download to save a .json file — all processed in your browser.
Common use cases
API data preparation
Convert a CSV export into JSON format ready to POST to a REST API or import into a JavaScript application.
Database seeding
Transform spreadsheet data exported as CSV into JSON arrays for seeding a MongoDB, Firebase, or similar NoSQL database.
Frontend mock data
Convert CSV data files into JSON fixtures for use as mock data in frontend development and testing.
Data format bridging
Bridge two systems where one exports CSV and the other imports JSON without writing any custom scripts.
Frequently asked questions
Is my data uploaded to a server?
No — conversion happens entirely in your browser using JavaScript. Your CSV data never leaves your device.
What JSON formats are supported?
You can output an array of objects (each row is a keyed object using header names), or an array of arrays (each row is a plain array including headers as the first row).
Are numbers auto-detected?
Yes, by default. Values that parse as valid numbers are stored as JSON numbers rather than strings. Uncheck "Auto-detect numbers" to keep everything as strings.
What if my CSV has commas inside fields?
Fields containing commas must be quoted in the CSV (standard CSV format). The parser handles quoted fields correctly.
Can I convert JSON back to CSV?
Not in this tool — JSON to CSV conversion is a separate tool. This tool is CSV-to-JSON only.
Is there a file size limit?
There is no enforced limit; the practical limit is your browser's memory. Files up to 50 MB convert reliably in most browsers.