A customer may see a $1 pending charge on their bank statement as part of the card authorization process. This is a temporary authorization charge and it will disappear from their statement.
When storing customer details, Stripe sends a request to the issuing bank for either a $0 or a $1 authorization to verify that the card is valid and the bank will allow it to be authorized.
Regardless of whether or not the authorization is declined, Stripe will reverse the authorization request immediately, but it may take 7-10 business days for the pending authorization to disappear from their bank statement.
Stripe will first attempt a $0 authorization for Visa, MasterCard, and American Express card sources. If the $0 authorization fails, then a $1 authorization will be attempted. Other card types will begin with a $1 authorization.