What is a backup payment method?

A backup payment method is a second card a customer already has on file, used to retry a subscription charge when the primary card fails. It turns a card that was replaced, expired, or temporarily declined into a recoverable event rather than a lost subscriber.

#Why it belongs in the recovery path

By the time a renewal fails, the customer has often already solved the problem elsewhere — a replacement card is in their wallet, and frequently already saved to the store. Retrying the same dead card on every rung of a ladder cannot succeed; trying the next card can.

#How WallaB.AI uses a backup card

• It is off by default. Charging an instrument other than the one the shopper chose is a merchant decision, so an unconfigured store never does it. The toggle lives on the merchant settings page.
• It fires inside dunning. Before a retry re-charges, WallaB moves the subscription to the customer's next active card on file and lets that retry hit it — see What is dunning?.
• It happens once per failure. A dunning case switches at whichever rung it first can, and never switches again, so a retry that crashes and re-runs cannot walk a customer down their whole wallet.
• It is recorded. The switch is written to the subscription's activity timeline with the card's brand, last four digits, and priority — never a card number or token — and a dedicated backup-card notice email can tell the shopper which card was charged.

#Card data never touches WallaB.AI

Cards are vaulted with Shopify. WallaB stores display metadata only — brand, last four digits, expiry month and year, and ordering — refreshed by a daily sync so the recovery path and the card-expiry warnings stay accurate as customers add and rotate cards.