Data Anonymizer - Mask Emails, IPs, Cards & Phones
Mask emails, IPs, credit card numbers, and phone numbers in text using built-in patterns or a custom regex rule.
Ready to Mask
Paste your text and click Mask Data to anonymize sensitive information
Data anonymizer
This tool masks sensitive values in text you paste in, such as log lines, chat exports, or CSV rows, directly in your browser. It replaces emails, IP addresses, credit card numbers, and phone numbers with partially hidden versions, or applies a regular expression pattern you write yourself.
How the masking works
Four presets are available. Email, IPv4, and credit card are checked by default; phone is off by default because phone number formats vary too much to catch reliably across countries. An email keeps its first letter and the domain visible and masks the rest of the local part, so john.doe@example.com becomes j*******@example.com. An IPv4 address keeps its first two octets and masks the last two, so 192.168.1.45 becomes 192.168.***.***. A credit card number keeps only its last four digits visible. A phone number keeps its last two characters and masks the rest. For anything the four presets do not cover, such as a name, employee ID, or internal reference number, the custom rule field takes your own regex pattern plus a replacement string; leave the replacement blank and it defaults to [REDACTED].
Worked example
Paste a login log line such as: 2024-05-20 14:32:01 User login. Email: sarah.chen@northgate-corp.com, IP: 10.44.22.198, Card: 4539 1122 8890 3345. With email, IPv4, and credit card checked, the output reads: 2024-05-20 14:32:01 User login. Email: s*********@northgate-corp.com, IP: 10.44.***.***, Card: ************3345. The timestamp and the word "login" stay untouched, since nothing in that text matches those three patterns.
Limitations
The presets match patterns, not meaning: a name, street address, or account number typed as plain text passes through untouched unless you write a custom rule for it. An invalid regex pattern is simply ignored, so the text near it stays unmasked with no warning shown. Masking only changes what appears in the output box; the text you pasted still sits in the browser's memory and clipboard history until you close the tab, so this does not replace securely deleting a file or encrypting it at rest. The tool sends nothing to a server; the replacement runs inside your browser tab.