CSV to JSON

Paste CSV data or load a CSV file and convert it to clean JSON in one click — free and instant. The delimiter is auto-detected and everything is converted locally in your browser.

How to convert CSV to JSON

  1. Add your CSV. Paste CSV text into the box above or press Load CSV file to open a .csv, .tsv or .txt file from your device.
  2. Check the options. Leave the delimiter on auto-detect (commas, semicolons, tabs and pipes are recognized), and tell the tool whether the first row contains column headers and whether numbers and booleans should be typed instead of quoted.
  3. Convert and export. The JSON appears instantly as you type or when you press Convert to JSON — copy it to the clipboard or download it as a .json file.

About this tool

This free CSV to JSON converter turns spreadsheet exports, database dumps and log data into JSON that is ready for APIs, JavaScript apps, configuration files or MongoDB imports. It implements a proper RFC 4180 parser: quoted fields, escaped quotes ("") and line breaks inside quoted values are all handled correctly, and European semicolon-separated files or tab-separated (TSV) files convert just as easily thanks to delimiter auto-detection. With headers enabled you get an array of objects keyed by column name; without headers you get a compact array of arrays.

Conversion runs entirely in your browser — your data is never uploaded, so it is safe for customer lists and financial exports, and large files convert in milliseconds. Working in the other direction? Use the companion JSON to CSV converter, or inspect a file first with the CSV Viewer.

Frequently asked questions

How does delimiter auto-detection work?

The tool counts the commas, semicolons, tabs and pipes that appear outside quoted fields in the first line and picks the most frequent one. If your data confuses the heuristic, simply choose the delimiter manually from the dropdown.

Why did my ZIP codes lose their leading zeros?

With Convert numbers & booleans enabled, a value like 00420 becomes the number 420. Untick that option to keep every value as a string — recommended for ZIP codes, phone numbers and IDs longer than 15 digits, where number precision would also be lost.

Can fields contain commas or line breaks?

Yes, as long as the field is wrapped in double quotes, e.g. "New York, NY". Quotes inside a field are escaped by doubling them (""), exactly as the CSV standard (RFC 4180) specifies, and multi-line quoted values are preserved in the JSON.

What happens if some rows have more or fewer columns?

Missing values become empty strings so every object has the same keys, and extra values get generated keys like column5. Fully empty lines are skipped.