Why did you charge me when my purchase failed?
Our payment provider (Adyen) sends a request to the issuing bank for either a $0 or a $1 authorization (different banks permit different amounts) to verify that the card is issued and the bank will allow it to be authorized. Regardless of whether or not the authorization is declined, Adyen reverses that authorization request immediately.
However, even if the bank declines the authorization, some people may still see an authorization for $1 on their credit card statement. The important thing to remember is that this is not a charge, and it will disappear from their statement; depending on the bank, it will be removed from their statement in anywhere from a few minutes to a few weeks.
Please note that Adyen can send a request for €1, which (depending on the current exchange rate) may show up as a transaction slightly over $1. (See current exchange rate)