Designing fraud checks for instant digital-goods delivery

Instant delivery is the entire pitch of digital-goods commerce: the customer pays, and the gift card code or license key lands in their inbox seconds later. But that same speed is what makes fraud so punishing. There is no shipping address to verify, no package to intercept, and once a code is revealed it cannot be unseen. A single stolen card can be drained across dozens of orders before the first chargeback arrives.

We have spent a lot of time thinking about this while building Kadokey, where gift cards are delivered instantly after checkout. Here is the layered approach we landed on.

Start with the threat model

Before writing a single check, list what you are actually defending against:

• Stolen card testing — bots probing small purchases to validate card numbers.
• Friendly fraud — real customers claiming they never received a digital item.
• Account takeover — reused credentials buying codes sent to a new email address.
• Crypto mempool games — paying with replaceable transactions, then swapping the transaction before it confirms.

Each of these needs a different control. A single fraud score from your payment processor helps, but it is not a strategy.

Layer 1: Pre-authorization signals

Reject cheaply, before money moves:

• Velocity limits on card fingerprint, email, IP, and device — for example, no more than a handful of orders per hour from one fingerprint. Card testers trip this within seconds.
• BIN and geography checks — a prepaid BIN from a different country than the IP is worth a second look, not an automatic decline.
• Minimum order economics — testing bots love tiny purchases. A sensible minimum order value makes probing you unprofitable.

These checks are stateless, fast, and run before you ever touch inventory.

Layer 2: Payment-specific controls

For card payments, require CVC and treat AVS mismatches as risk signals, then decide based on order value: auto-approve small, review large.

Crypto payments need their own playbook. There is no chargeback mechanism, but there is mempool risk:

• Require a number of confirmations scaled to order value (one for small orders, several for large ones).
• Watch for replace-by-fee (RBF) flags on incoming transactions; never release goods while the payment is still replaceable.
• Screen addresses against sanctions lists. This is table stakes for compliance and cheap to implement via public list APIs.

Layer 3: Fulfillment gating

This is the layer most stores skip, and it is the most important one for digital goods. Payment authorization is not the same as "safe to deliver."

We use stepped release:

• Small orders from clean fingerprints → instant, automated delivery.
• Medium risk → delayed delivery (15–60 minutes) with an email ownership check.
• High risk or high value → manual review queue.

A short, predictable delay on a fraction of orders costs almost nothing in conversion and kills the attacker's favorite property of your store: instant, guaranteed payout.

Also: never render the full code on the receipt page before the delivery email is confirmed sent. It sounds obvious, but plenty of stores display the key in the browser immediately, which makes session hijacking a direct path to inventory theft.

Layer 4: Post-fulfillment feedback loops

Every chargeback should feed back into your fingerprints:

• Link the chargeback to the card fingerprint, device, email, and IP that placed the order.
• Auto-flag repeat fingerprints for manual review on their next order, before fulfillment.
• Track your false-positive rate — the share of flagged orders that turned out legitimate. If review-queue customers complain about delays, your thresholds are too tight and you are burning real revenue to stop theoretical fraud.

The tradeoff you cannot avoid

Every fraud control rejects some legitimate customers. The goal is not zero fraud — it is maximizing profitable order flow. Measure two numbers weekly: fraud loss rate and false-positive rate. Tune thresholds until the marginal dollar of fraud prevented costs you less than a dollar of good orders.

If you are building a digital-goods store and want to see what instant delivery looks like with these layers in place, Kadokey's storefront is a decent reference — gift cards across dozens of brands, delivered in seconds, with the checks above running behind every order.