Edit a CSV file online — without uploading it
Fix a typo in row 40,213, rename a header, replace every “N/A” with an empty cell, delete the duplicate signups — the small surgical edits CSVs always need, without round-tripping through Excel (which likes to “help” by reformatting your dates and ZIP codes on save). Double-click any cell to edit it; use find & replace (plain or regex) for bulk changes; rename or hide columns before export.
Your original file is never modified — edits live in your browser until you export a corrected copy, and none of it is uploaded anywhere. That makes this safe for the files you’d never paste into a web form: customer lists, payroll exports, anything with real names in it.
Drop a CSV, TSV or Excel file here
.csv · .tsv · .txt · .csv.gz · .xlsx — files up to 4 GB open here, in your browser. Nothing is uploaded; the file is read in place on your device.
Filters combine with AND. Use the search box for a quick any-column match. Regex filters use JavaScript syntax.
Untick to hide a column (hidden columns are left out of exports). Type to rename — renames apply to exports too.
Exports include your filters, sort, edits and cleanups. Hidden columns are left out; renamed headers apply. The file is generated on your device — nothing is sent anywhere.
How it works
- Open the file. Double-click any cell to change it; Enter saves, Esc cancels.
- Use Clean → Find & replace for bulk edits — preview shows how many rows will change before you commit.
- Rename headers or hide columns in the Columns panel; hidden columns stay out of the export.
- Export the corrected file as CSV (or Excel/JSON). The original on disk is untouched.
Why not just edit in Excel?
Because Excel edits more than you asked it to. Open a CSV, change one cell, save — and every date column has been rewritten into your locale’s format, ZIP codes like 02134 have lost their zero, and 16-digit IDs now end in 000 because they were rounded to 15 significant digits. None of that is visible until something downstream breaks. A structure-preserving editor changes the cell you touched and reproduces everything else exactly as it arrived.
The same applies to encodings: files with accented names that arrive as UTF-8 can leave older Excel versions as something else entirely. Here the file is exported back as UTF-8 (with an optional BOM so Excel reads the accents correctly if the file is headed there next).
Good to know
- Edited cells get a green mark so you can see what you’ve touched before exporting.
- “Undo all cleanups” reverts every edit, filter and transform in one click — the original data is always still there underneath.
- Regex replace supports capture groups: find
(\d+)-(\d+), replace$2/$1to swap number pairs.
Frequently asked questions
Does editing here change my original file?
No. Browsers can’t silently write to files on your disk, and this tool doesn’t ask for write access. Edits exist in the viewer only until you download the corrected copy — the original stays exactly as it was, which doubles as your undo.
Can I edit huge files?
Yes — the editor uses the same streaming engine as the large-file viewer, so editing works in multi-hundred-MB files too. Cell edits are stored as an overlay, not a rewrite, so even a 2 GB file takes edits instantly.
Can I add or delete rows and columns?
You can delete columns (hide them and they’re dropped from exports), remove rows via duplicate removal, empty-row cleanup or filters, and edit any existing cell. Inserting brand-new rows or columns isn’t supported yet — for that, a spreadsheet is the right tool.
Is regex find & replace supported?
Yes — tick “Regex” in the Clean panel. JavaScript regex syntax, with capture groups in the replacement ($1, $2). Preview first: it reports how many rows would change without committing anything.