Mask emails, phone numbers and card numbers in a CSV
Hide personal details in a CSV before sharing it with a developer, a contractor or an AI tool. Masking runs in your browser; the file is not uploaded.
Before a customer list goes to a developer, a test environment or a chat assistant, it is safer to hide the parts that identify people. This tool masks three kinds of value and keeps enough to stay useful: the first letter and domain of an email, and the last four digits of phone and card numbers.
What gets masked
- Emails:
alice.j@example.combecomesa***@example.com. - Phone numbers: numbers written like phone numbers, with a
+, brackets, or groups separated by spaces, dots or dashes.+44 20 7946 0958becomes+** ** **** 0958. - Card numbers: 13 to 19 digits that pass the card checksum, or anything written in four groups of four. The last four digits are kept.
What is deliberately left alone
Bare runs of digits such as order numbers, account numbers and ISBN barcodes, and dates. The sample includes an order number and an ISBN so you can see them come through unchanged.
Limits
Masking is pattern matching, not a guarantee. It does not find names, addresses, national ID numbers or free text that mentions a person. Look through the output before you share it, and remove whole columns you do not need.