Mask sensitive data for sharing
Remove columns or replace their values with consistent placeholders. Review what remains before exporting the table.
Your data stays in this browser. Nothing is uploaded. Privacy details
1 Load your data
Up to 5 MiB. Loading new data replaces the current data and column choices.
Or paste text
Preview the first 5 data rows
No data loaded.
2 Choose what to share
Every column starts as Remove column. Choose Consistent placeholders to retain repeated-value relationships, or Keep original values to include the source text.
Placeholders match exact cell text within each column. Blank cells remain blank. Numbering starts from the first occurrence in the loaded table; it can change with another file or row order. Values in different columns use separate placeholders.
3 Review and download
Check the original columns you kept, free text, column headings, and combinations of values that could identify someone. Masking does not guarantee anonymity. Repeated values, blank cells, row order and record counts remain visible.
Plain text uses tabs between columns and quotes cells containing tabs or line breaks. Spreadsheet protection applies to CSV and TSV.
Protection adds an apostrophe to potentially executable cells, including negative numbers. Turn it off for exact cell text.
Table preview shows the first 100 rows. Copies and downloads include every output row.
No output yet.
View formatted output
Preview limited to 30,000 characters. Copy and download include the complete output.
Prepare a table for sharing
Load a local file or paste a table. Choose an action for each column, then select Preview masking. Review the list of removed, replaced and unchanged columns alongside the first 100 output rows. Confirm the review to enable copy and download. Changing a column choice clears the result and review confirmation.
Try an example loads fictional contacts. It replaces IDs and names with placeholders, removes emails and notes, and keeps team names. The repeated Asha Example name receives the same placeholder in both records.
Consistent placeholders replace whole cells. The tool does not detect sensitive content inside a cell, mask part of a value, or remove identifying information automatically. Source values and placeholder mappings are never included as extra export columns or separate files. Column headings stay unchanged. Inspect the complete result before sharing it.
Privacy and limits
Source tables, column choices and results stay in browser memory. Clear all data removes them and cancels pending work. Reloading clears tool data. Only the site theme preference is stored. Copy and download act only when selected; related links do not transfer data.
CSV, TSV, Excel, JSON and JSON Lines reuse the local data-file converter. Choose a worksheet or JSON collection when required. Excel formulas use saved results, without recalculation. Text is UTF-8. Malformed quoting or uneven text rows prevent loading.
Input allows 5 MiB, 20,000 rows, 100 columns and 500,000 cells including headings. Output allows 20 million characters. Hosted processing uses a local worker with a 20-second deadline. Direct local-file use can pause the page. Clipboard access may need HTTPS or permission. Excel support uses the locally bundled Apache 2.0 licensed SheetJS library.