CSV to JSON & JSON to CSV Converter
Convert spreadsheet data to JSON for an API, or turn JSON back into a CSV you can open in Excel. Handles quoted fields, commas inside values and line breaks properly. Nothing is uploaded.
Drop a .csv or .json file here, or click to choose
How to Convert CSV to JSON
- Paste your CSV into the left box, or drop a
.csvfile below it. - Leave First row is a header ticked if row one holds your column names — those become the JSON keys.
- Press CSV → JSON. Going the other way, paste JSON on the right and press JSON → CSV.
- Copy the result or download it as a file.
Why CSV Is Trickier Than It Looks
Splitting a CSV on commas breaks the moment a value contains a comma. Real CSV follows RFC 4180, and this converter implements it properly:
- Quoted fields —
"Smith, John"stays one value, comma and all. - Escaped quotes — a doubled
""inside a quoted field means one literal quote character. - Line breaks inside values — a quoted field may span several lines without ending the row.
- Other delimiters — much of Europe exports semicolon-separated files; tabs and pipes are also common. Auto-detect works this out for you.
Number and Boolean Detection
With detection on, 42 becomes the number 42 and true becomes a real boolean, which is usually what an API expects. Values with leading zeros are deliberately kept as text, so postcodes, phone numbers and IDs like 007 are not silently mangled into 7 — the classic spreadsheet bug. Switch detection off if you want every value to stay a string.
JSON to CSV
Give it an array of objects and every unique key across all objects becomes a column, so rows with missing fields simply get empty cells. Values containing your delimiter, a quote or a newline are quoted and escaped automatically, meaning the file opens cleanly in Excel, Numbers and Google Sheets. Nested objects and arrays are written as JSON text inside the cell, since CSV has no concept of nesting.
Frequently Asked Questions
Is my data uploaded to a server?
No. Parsing and conversion happen entirely in your browser, so it is safe for customer lists, exports and other confidential data.
Does it handle commas inside values?
Yes. Properly quoted fields are parsed to the RFC 4180 standard, including doubled quotes and line breaks inside a quoted value.
Why did my JSON to CSV conversion fail?
JSON to CSV needs an array of objects, such as [{"a":1},{"a":2}]. A single object is wrapped into a one-row file automatically, but a bare number, string or deeply nested structure has no sensible table form.
Will Excel open the CSV correctly?
Yes. Fields containing delimiters, quotes or newlines are escaped to the standard. If your regional settings expect semicolons, choose Semicolon as the delimiter before converting.