CSV Viewer
Open a CSV file as a real editable table, fix a value, add a row or column, then export it back out. No spreadsheet software needed.
Click to choose a .csv file, or drag and drop it here
Edit any cell directly in the table below, then export.
How it works
Your file is read as text with the browser's FileReader API, the delimiter is
auto-detected by counting commas, semicolons, and tabs in the first line, and a
quote-aware parser (RFC 4180 style: quoted fields can contain commas and line breaks,
"" means a literal quote) turns it into an in-memory grid. The table you see
is real HTML: every cell is an <input> element wired to write changes
straight back into that grid, which is why editing feels instant and why undo works
per-cell like any form field.
Export is where this tool is more careful than most. The serializer only quotes fields
that actually need it (ones containing a comma, quote, or line break), doubles any
embedded quotes, and joins rows with CRLF (\r\n) line endings, exactly what
RFC 4180 specifies and what Excel expects. One consequence: a file can round-trip with
identical data but slightly different bytes, because inconsistent quoting in the original
gets normalized. That's cosmetic, not data loss.
Nothing here touches a server. Open DevTools' Network tab, load a CSV, edit a few cells,
download the result: you'll see zero requests involving your data. The download itself is
a Blob assembled in memory and saved by your browser.
Common questions
Does this handle large CSV files?
It's built for typical exports, spreadsheets, and reports, generally up to a few thousand rows. Very large files (tens of megabytes) may feel slow since everything renders as real table cells.
Can I add or remove columns?
You can add columns and rows with the buttons below the table. To remove a column, clear its header and leave the cells blank, or edit the exported file directly.
What happens to my data?
It stays in your browser the whole time. Nothing is uploaded, and closing the tab clears it, so export before you navigate away.