GeraDados
Test credit card numbers
Build a primary account number that passes the Luhn check and uses a familiar test prefix. A real gateway still declines it.
How it works
Luhn walks the digits from the right, doubles every second one, and subtracts 9 when a double is over 9. The final digit makes the total a multiple of 10. It catches typos. It does not mean the card exists.
The generator uses 16 digits for Visa (prefix 4), Mastercard (prefix 55) and a sample Elo prefix, and 15 digits for American Express (prefix 34). The classic sandbox value 4242 4242 4242 4242 is listed beside the generator.
Questions
Will this charge a card?
No. There is no merchant account and no network authorization on this page.
Why does my validator still fail?
Some forms also expect a brand range, a length, or a future expiry. Generate those fields in your fixture separately. This page only checks the number.
Are these safe to commit in a repo?
Yes if the file says they are test PANs. Do not commit real customer numbers next to them.