What is Card on File?

A card on file is a payment card an operator has stored so it can be used again without re-entering the number. The card details themselves are usually held by the payment provider rather than the operator, and what is stored on the operator's side is a token that points at them. The security position is better than it sounds. Tokenised storage means a breach of the operator does not expose card numbers, and stored cards can still be sent through additional authentication when a bank asks for it. The risk that remains is account takeover: if somebody reaches your account, a stored card is a stored payment method. The more interesting effect is behavioural, and it is worth being honest about. Typing a card number is friction, and friction is a pause. Removing it turns depositing from a task into a tap, which is exactly why operators offer it and exactly why it deserves a moment's thought from anyone who has ever deposited more often than they meant to. That cuts both ways, and the useful conclusion is not simply to avoid it. A stored card paired with a deposit limit is a reasonable arrangement: the limit does the work the friction used to do, and it does it more reliably because it is a rule rather than an inconvenience. A stored card with no limit set is a system with the brake removed. Both are one screen apart in most cashiers, and only one of them is a decision you made on purpose.