Data Anonymizer
Mask, redact, hash, or shuffle columns — all in your browser.
Your data stays in this tab — nothing uploadedAnonymize and mask sensitive data in CSV files
About this data anonymizer
Upload or paste a CSV file and choose a masking rule for each column: keep it unchanged, mask it (preserve first/last characters and replace the rest with asterisks), redact it entirely, hash it with SHA-256 (consistent: same input always produces the same hash, preserving referential integrity across columns), replace it with realistic fake data, shuffle the values randomly within the column (preserving the statistical distribution), or generalize numbers and dates to broader ranges.
Client-side anonymization is the only kind that can honestly promise your data was never exposed. Upload-based tools process your data on their servers — even briefly — which means your PII transits the network and exists in someone else’s memory. This tool never sends anything: the Web Crypto API handles hashing locally, and all fake data is generated in the page’s JavaScript. Use it to prepare datasets for development, testing, demos, or GDPR-compliant sharing.
FAQ
Can I hash a column and still join it with another table?
Yes. SHA-256 hashing is deterministic: the same input always produces the same hash. If you hash the "email" column in two different files, matching emails will have matching hashes, so you can still join or deduplicate across datasets without revealing the actual email addresses.
What does "shuffle" do differently from "fake"?
Shuffle keeps the real values but rearranges them randomly across rows, so the column’s statistical properties (mean, distribution, unique count) are preserved but no value is associated with the correct row. Fake replaces every value with randomly generated data that looks realistic but has no statistical relationship to the original.
Is this tool compliant with GDPR?
This tool can help you produce anonymized datasets, but compliance depends on your specific situation and the anonymization rules you choose. Properly hashed or redacted data may qualify as anonymous under GDPR, but consult your Data Protection Officer or legal counsel for a definitive assessment.