CSV to JSON & JSON to CSV Converter
Turn a spreadsheet exported as CSV into JSON ready for your API, or convert a JSON array into a CSV that opens in Excel or Google Sheets. Handles quoted fields, line breaks inside cells and any delimiter. Your data never leaves your browser.
How to convert CSV to JSON
- Paste CSV content or open a .csv file (cells copied straight from Excel or Google Sheets work too — they paste as tab-separated values).
- Leave the delimiter on "Auto-detect" or pick one, and say whether the first row holds the column names.
- Click "CSV → JSON". For the reverse, paste a JSON array and click "JSON → CSV".
- Copy the result or download it as .json or .csv.
CSV vs JSON: when to use each
CSV (comma-separated values) is the universal format for tabular data: Excel, Google Sheets, databases and almost every CRM export it. JSON is the standard format of web APIs and JavaScript, and it supports nested structures.
This converter follows RFC 4180: quoted fields may contain delimiters, line breaks and escaped quotes (""). When converting JSON to CSV, the keys of every object are merged into the column list, and nested values are stored as JSON text so no information is lost.
Frequently asked questions
My CSV uses semicolons — does that work?
Yes. Excel in many European locales exports CSV with semicolons. "Auto-detect" picks it up automatically, or you can select it manually.
What happens to numbers and empty cells?
With "Detect numbers & booleans" on, 42 becomes a number, true/false become booleans and empty cells become null. Numbers with leading zeros (such as ZIP codes like 02134) stay as strings so nothing is lost.
How is nested JSON converted to CSV?
Every top-level key becomes a column. If a value is an object or an array, it is written as JSON text inside the cell so you can recover it later.
Is there a size limit, or is my data uploaded?
Nothing is uploaded: the conversion runs in your browser. The only limit is your device's memory; files of several megabytes convert without trouble.