Anonymize PII in CSV files
Remove or mask personally identifiable information from CSV exports before sharing, testing, or publishing. CSViser redacts emails, phone numbers, credit card numbers, SSNs, and IP addresses — column by column, with a preview before applying.
Upload your CSV with PII to anonymize
CSV, XLSX, or JSON — any size
Free account — takes 10 seconds to sign up
After upload: go to the Anonymize tab → add rules (column + PII type + method) → Apply.
What is PII and why anonymize it?
Personally identifiable information (PII) is any data that can be used, alone or in combination, to identify a specific individual. In CSV exports from CRMs, e-commerce platforms, analytics tools, and databases, PII commonly appears as email addresses, phone numbers, full names, postal addresses, IP addresses, credit card numbers, and social security numbers.
You need to anonymize this data before:
- Sharing datasets with contractors, partners, or analytics teams
- Using production data in development or test environments
- Publishing sample datasets or demo files publicly
- Complying with GDPR, CCPA, HIPAA, or internal data governance policies
Supported PII types
Email address
Detected by standard email pattern. Redact replaces with [REDACTED];
Mask replaces the local part with asterisks — al**@example.com —
preserving the domain structure for debugging.
Phone number
Detected by phone pattern (E.164, national formats with dashes/dots/spaces).
Redact: [REDACTED]. Mask: last four digits visible — ****2671.
Credit card number
Detected by 13–19 digit pattern with optional separators. Mask: shows last four
digits — **** **** **** 1234.
SSN (Social Security Number)
Detected by NNN-NN-NNNN pattern. Redact or mask last four digits.
IP address
Detected by IPv4 and IPv6 patterns. Mask: last octet replaced —
192.168.1.***.
Custom regex
Provide your own regular expression to match any pattern — order numbers, internal IDs, postal codes, or any other structured data you need to remove.
Redact vs Mask
Redact replaces the entire cell value with [REDACTED].
The data is completely removed — no information about the original value is preserved.
Use for the highest level of privacy protection.
Mask replaces most characters with asterisks but preserves enough
structure to be useful for debugging and QA — you can still tell that the value
was an email address, or confirm that a phone number ended in 2671,
without exposing the full value. Use when the anonymized dataset will be used for
development or testing where some context is helpful.
Frequently asked questions
Can I apply different rules to different columns?
Yes. Each rule is scoped to a specific column and PII type. You can redact emails in one column, mask phone numbers in another, and apply a custom regex to a third — all in the same operation.
What if a cell doesn't match the PII pattern?
Only cells whose full value matches the selected PII pattern are anonymized. Non-matching cells are left unchanged. This means a "Phone number" rule on an email column will not affect any cells — patterns are matched against the whole cell, not sub-strings.
Is the original file deleted after anonymization?
CSViser automatically deletes all uploaded files after 24 hours. No PII is retained on the server beyond that window. For immediate deletion, use the Quick Process (zero-retention) mode from the dashboard — files are processed entirely in memory and never saved to storage.