Anti-fraud is a system that scores the risk of every operation before it goes through and stops the suspicious ones. It looks not at a single buyer but at behaviour: how many attempts in a row, from which country, how typical the amount and the item are for this merchant.
What it scores
- Attempt frequency: several declines in a row from different cards is a classic sign of carding.
- Geography: a mismatch between card country, IP and delivery address raises the risk.
- Amount and item: a ticket unusual for the merchant stands out against normal operations.
- The history of the card and the device across the payment system network.
Why it fires on honest buyers
- It estimates probability, not fact: some legitimate operations inevitably look suspicious.
- A buyer may pay while travelling, from someone else device or through a VPN — all deviations from the norm.
- A first purchase on a new card looks riskier than a repeat one.
What to do as a merchant
- Do not ask the buyer to retry repeatedly: a series of declines only pushes the risk score up.
- Offer another method — SBP or a payment link — instead of re-entering the same card.
- Keep the item description and merchant name clear: mismatches deepen suspicion.
Why a bank declines a payment with money on the card is covered separately.
