#7bystats-duplicate-cards
shy vapor
Hi there 👋 apologies for the delay.
When you mention people singing up with the same card under multiple accounts, is that multiple accounts within your system or are you working with Stripe Connect where there are multiple Stripe accounts involved?
native cairn
No, they are accounts within my system.
shy vapor
Gotcha, when you create a Payment Method for a card, then it will have a card.fingerprint field which is a value calculated based off of the card details and is unique for each card. You can use this to check if another Payment Method was already created for a card:
https://stripe.com/docs/api/payment_methods/object#payment_method_object-card-fingerprint
native cairn
So it can be done right? I want to avoid customers creating accounts with fake email addresses and thus gaining access to a discount coupon again and again. But if I require CC details, and if it is possible to prevent customers from creating multiple accounts with the same CC, then it won't be a problem.
shy vapor
Yes, you can adjust your flow so that you create the Payment Method first (before processing a payment) and then check to see if you already have a Payment Method with a matching fingerprint. If so, then you can block the rest of your flow from executing.
native cairn
Perfect! I haven't started the website yet, and no account here at Stripe. But soon.
How do I make this work later?
shy vapor
This guide walks through the process to save the Payment Method first, and then process a payment later (if the card isn't a duplicate):
https://stripe.com/docs/payments/save-and-reuse
It doesn't cover checking the fingerprints though, that is custom code that you'll need to build.
native cairn
Okay. thanks for the help
shy vapor
Any time!