Mask sensitive data in CSV files online — anonymize emails, names, phone numbers, and IDs before sharing externally.
Free for files up to 5 MB and 10,000 rows. Files are processed in your browser — nothing is uploaded to a server. No account required.
Replace sensitive values with masked ones before a file leaves your control. Tick the columns to mask and choose how: partial keeps the first and last two characters, full replaces every character with a dot, email keeps the first letter and the whole domain, and hash swaps the value for a short deterministic token.
Handing a production customer export to an outside contractor, attaching a data sample to a bug report, or building a demo dataset are the situations that call for it. Because hashing is deterministic, the same email produces the same token everywhere in the file, so you can still count distinct users or line up two masked files afterwards.
Masking runs in this browser tab and this tool uploads nothing. The hash is a short non-cryptographic fingerprint meant for pseudonymization, so treat the output as reduced risk rather than as anonymized data.