CSV Viewer

CSV Viewer opens, filters, edits, and compares CSV files on your device. It runs as a desktop app or in the browser, and it never uploads your files.

Try it in your browser. No install is needed.

Features

• Sort, filter, and search large CSV files.
• Edit cells, rows, and columns, with undo and redo.
• Keep several files open in tabs. Each tab has its own edits and query.
• Compare two files by a key and see which cells and rows differ.
• Count the values in a column.
• Copy a cell or a whole column.
• Export the whole working copy or just the current view to a new file. CSV Viewer never overwrites the source file.
• Pick light or dark mode, one of four color palettes, and a collapsible sidebar.

Open a file

Drop CSV, TSV, or TXT files into the window, or click Open CSV. You can drop several files at once. Tabs that are already open keep their edits.

If a file opens with the wrong columns, click Parse options beside Open CSV and set the delimiter and the header mode. The settings apply to the next open or Reopen.

Reopen reloads the source into the same tab. It resets the tab's query, selection, stats, and edit history. If the tab has unexported changes, CSV Viewer asks before it discards them.

Edit and export

Double-click a cell to edit it. CSV Viewer keeps every value as text, so codes with leading zeros keep their zeros. Edits change a working copy, and the tab shows Unexported Changes until you export the whole working copy.

• To insert a row, select one row and insert above or below it. The current query can hide the new row.
• To append a row, clear the row selection and the query first.
• To delete rows, select them and delete.
• To rename, insert, or delete a column, right-click its header. A column name must be nonblank, unique, and not reserved. You can't delete the last column.
• To undo or redo a cell, row, or column change, click Undo edit or Redo edit. Undoing a column deletion restores the column's values and position.

To save your edits, click Export CSV. The export contains the whole working copy with the file's delimiter and header settings. Search, filters, and sort don't affect it. On desktop, you pick a destination, and CSV Viewer refuses to overwrite the source file. On the web, the browser downloads the file. Closing a tab with unexported changes asks for confirmation.

To extract matching rows, open Export options beside Export and choose Export current view. It includes every matching row in the current sort order, even beyond the loaded grid. All columns keep their working-copy order, regardless of row selection or dragged headers. The menu shows the matching count and disables the action while the count is unresolved or zero.

An active cell editor commits first; a failed commit keeps its draft open. Delivery suggests a -view filename and keeps the current delimiter and header settings. View export preserves Unexported Changes and undo/redo history, even when every row matches.

Search, copy, and count values

Global search matches across all columns. Column headers sort and filter. On a text column, the filter lists the column's top values with their row counts: search for text, or check and uncheck values to keep or hide them. Right-click a text cell to filter to that value or exclude it. Clear query resets the search, filters, and sort.

Press Ctrl+C to copy the focused cell. To copy a column, right-click its header and choose Copy column. The copy holds the values that match the current query, in the current sort order, one per line, without the header. Null values become empty lines.

The stats panel shows Column Value Counts for the focused column. To count another column, choose it in Stats Column. Counts and percentages follow the current search and filters, and they update after edits. Blank values and null values are counted separately.

Compare two files

Both files need the same column names, in any order. Open both files, click Compare, and choose a key of one or more columns. The key value must be present and unique in every row of both files. If it isn't, CSV Viewer lists the blank and duplicate key values.

The comparison uses both working copies, including unexported changes, and ignores search and filters. It shows changed cells, unchanged rows, and rows found in only one file. You can show only the differences, swap the baseline and the candidate, or cancel a running comparison. If you edit or reopen either file, the result is marked outdated until you refresh it. Closing a source tab also closes its comparisons.

Keyboard shortcuts

Press Ctrl+/ or click Keyboard shortcuts in the sidebar to show the shortcut panel. On macOS, use Cmd instead of Ctrl.

Shortcut	Action
F2 on a column header	Rename the column.
F2 on a cell	Edit the cell.
Ctrl+C on a cell	Copy the cell.
Ctrl+Shift+A	Copy the focused column. Doesn't work inside a text field.
Ctrl+/	Show or hide the shortcut panel.

Desktop and web differences

Behavior	Desktop	Web
Opening files	Native file dialog or file drop.	Browser file picker or file drop.
Recent files	Kept across restarts. Missing files drop off the list.	None. Files last only for the page session.
Opening the same file again	Focuses its existing tab.	Opens a new, independent tab.
Export	Saves to a destination you pick.	Downloads the file.
File size	Limited by your machine's resources.	100 MB per file and 200 MB across all open files, counted in source bytes.

On the web, a few more rules apply:

• If your browser isn't supported, CSV Viewer says so and points you to the desktop app.
• Reloading or leaving the page loses your files and edits. The browser asks first if you have unexported changes.
• If the data engine stops, the page shows The workspace stopped. Click Reload CSV Viewer to start a new, empty session.

Limitations

• Values are plain text. CSV Viewer doesn't validate numbers, dates, or booleans.
• You can't append a row while a sort, filter, or search is active.
• Dragging headers changes their visual arrangement; exports keep working-copy column order.
• CSV Viewer has no formulas, pivot tables, charts, joins, or SQL editor.

Run from source

You need Node.js 24 or newer and pnpm 10.34.2. If you use mise, mise.toml pins both.

pnpm install
pnpm run dev:desktop

To run the web app, use pnpm run dev:web instead.

pnpm build builds both apps. pnpm package builds desktop installers into release/: a Windows installer and portable executable, a macOS DMG, or a Linux AppImage, depending on your platform.

To test, debug, or change the code, see CONTRIBUTING.md.