Excel / CSV Data Masking
Tick the rules first, then drop in the spreadsheet. Names, companies, phone numbers and ID cards are masked by a full-text scan, and nothing is uploaded. This tool is not compliance certification.
100% browser-based · files never uploaded
1Choose the masking rules
Once ticked, matching text inside each cell is masked in place. Secrets and credentials are always on. You can also add your own keyword rules.
Add a custom masking rule
A new rule can be ticked like the ones above. It only lives for this session and never stores any table content.
2Import the spreadsheet
🔒 Your files never leave your browser
Related tools
Frequently asked questions
- Is the file uploaded?
- No. Parsing and masking both happen in the browser on this computer — TwoThink never receives the contents of your spreadsheet.
- Can the masked file be reversed?
- Masks, pseudonyms and dropped columns cannot be reversed. Hashes are one-way: the same original value gives the same hash inside one file, which makes reconciliation easy, but we do not offer decryption. Keep an unmasked copy yourself.
- Does this count as PIPL / classified-protection compliance?
- No. This tool only helps you handle fields before you share a file; compliance still depends on your own policies and legal advice.
- Why are amounts not masked automatically?
- Sales and collection sheets usually need the real figures. When you do need a range, open the column overrides and switch that column to "Amount range" or "Drop column".
- What is the difference between masking and column overrides?
- By default, the rules you tick are scanned inside every cell, so mixed-in notes are masked too. If one whole column must be forced into a mask, pseudonym, hash or dropped, use the column overrides.
- Can encrypted Excel files be opened?
- Not yet. Remove the password in Excel first and then drop the file in. Save an old .xls as .xlsx.
- How does this relate to converting CSV to JSON?
- If the result is meant for a program, mask the data here first and then use TwoThink Dev to convert between CSV and JSON.