CSV Viewer & Editor

About CSV Viewer & Editor

Open a CSV or TSV file and read it the way it was meant to be read — as a table with aligned columns, numbered rows and typed cells — then change it in place. Click any cell and edit it, rename a column by clicking its header, insert and delete rows, add and remove columns, sort by any column, and filter down to the rows you are looking for. The raw CSV sits in the left pane the whole time and stays in step with the table: edit a cell and the text updates, edit the text and the table redraws. That matters because CSV is a text format with awkward corners — quoting, embedded commas, embedded newlines — and this shows you both views at once so a quoting problem is obvious instead of mysterious. Nothing is uploaded; the file is read and rewritten entirely inside your browser tab.

Key features

• A real editable table, not a preview — click any cell to change it, Enter to commit, Escape to cancel, Tab to move to the next cell
• Two live views of the same data: the raw CSV on the left and the table on the right, each updating as you edit the other
• Delimiter auto-detected from the first line — comma, semicolon, tab or pipe — or set by hand when the guess is wrong, so European semicolon exports and TSV files open correctly
• Row and column editing: insert a row below any row, delete a row, append a row or column, delete a column, and rename a header by clicking it
• Sorting that understands its data — numbers sort numerically so 10 lands after 2, ISO dates sort chronologically, and empty cells sink to the bottom in both directions
• Row filter with the matching text highlighted in place, and a count of how many of your rows matched
• Cells coloured by type, the same colours the raw pane uses: numbers, booleans, ISO dates, text and empty cells each read differently at a glance
• Correct quoting on the way out — a cell containing a comma, a quote, a newline or padded spaces is quoted and escaped, and every other cell is left bare
• A warning when rows are ragged, naming how many had fewer columns than the widest row, since that is almost always an unclosed quote upstream
• Two clean-up actions: trim leading and trailing spaces from every cell, and delete every row that is entirely empty
• Undo and redo for every edit — Ctrl+Z / ⌘Z, or the toolbar buttons — covering the destructive ones a spreadsheet makes you regret: a sort, a deleted row or column, drop-empty-rows, even clearing the whole file
• Open a .csv, .tsv or .txt file up to 10 MB, or paste straight into the left pane; download the result as .csv, or as .tsv when the delimiter is a tab
• CRLF line endings on demand, for the Windows tools and older Excel versions that expect them
• Large files stay responsive — rows are rendered 200 at a time with a button to show more, so a 50,000-row export opens without freezing the tab
• Runs entirely in your browser — a customer export or a payroll file is never sent anywhere

How to use it

1. Click Open file to load a .csv or .tsv from your machine, or paste CSV straight into the left pane.
2. Check the delimiter badge and the table: if the columns are wrong, pick the delimiter by hand instead of Auto-detect, and turn "Header row" off for a file whose first line is data.
3. Click any cell to edit it. Press Enter to commit, Tab to move to the next cell, Escape to abandon the change.
4. Use the row controls that appear on hover to insert or delete rows, the buttons above the table to append a row or column, and the header buttons to sort or delete a column. Anything you change can be undone with Ctrl+Z or the Undo button.
5. Type in the filter box to narrow the table to matching rows, then edit those rows directly — edits land on the right record even while filtered.
6. Copy the CSV from the toolbar or click Download to save the edited file.

Tips & common mistakes

• If a file opens as one wide column, the delimiter is wrong. Semicolons are the usual culprit: exports from Excel in most of Europe use them, because the comma is the decimal separator there. Switch the delimiter from Auto-detect to Semicolon and the columns appear.
• Turn "Header row" off for a file whose first line is already data. With it on, that first record is consumed as column names and quietly disappears from the row count — the giveaway is a header that reads like a record rather than like labels.
• Ragged rows are worth investigating rather than accepting. The padding keeps the table usable, but the cause is nearly always a quote that was opened and never closed, which means one cell has swallowed the rest of the file. The left pane is where you will see it: everything after the stray quote is coloured as one long string.
• Sorting rewrites the data, it does not just reorder the view — what you see is exactly what Copy and Download give you. That is undoable like any other edit, so a sort you did not mean is one Ctrl+Z away rather than a reason to re-open the file.
• Nothing you do to the table is one-way. Undo steps back through cell edits, sorts, inserted and deleted rows and columns, the clean-up actions, and opening a file over your work; redo walks forward again. Typing in the raw pane collapses into one step per burst rather than one per character, so undo moves in useful jumps — and while the cursor is in that pane the browser’s own undo still works normally for finer backtracking.
• Identifiers with leading zeros are safe here. A cell reading 0042 is treated as text, not as the number 42, so it keeps its digits and sorts alphabetically — which is the opposite of what happens when the same file is opened in a spreadsheet and saved again.
• Quoting is handled for you on the way out, so type a comma or a line break into a cell without thinking about it. The cell is quoted automatically, and cells that do not need quotes do not get them — the file stays as close to what you opened as the edits allow.
• Trim cells before comparing or importing. Trailing spaces are invisible in every view of a CSV and are the reason a lookup or a join silently matches nothing; one click removes them from every cell at once.
• The filter is a view, not a delete. Filtering to a subset and hitting Download still saves the whole file — to actually cut rows, filter to find them and use the per-row delete, or clear the filter and use "drop empty rows".
• Blank lines are dropped when the file is read. They are almost always padding at the end of an export rather than records, so a single-column file with deliberate gaps in it is the one case where this tool loses something — keep a placeholder character in those rows.
• Turn on CRLF endings if the file is going back to a Windows tool or an older Excel. Modern software reads either, but a few importers and some legacy parsers still expect carriage returns and will treat the whole file as one line without them.
• When you need the data as records rather than as a table, send it on: the CSV to JSON converter turns it into an array of objects, and the JSON to Excel converter will give you a real .xlsx workbook.

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