Three Plus-tier fraud builds with real ROI: validation functions that block known-bad patterns pre-payment (PO boxes for high-value goods, reshipper addresses, malformed data), signal capture that enriches [order evidence](/blog/shopify-order-data-dispute-evidence), and selective friction — extra verification steps rendered only for risky carts. The principle: checkout is the one moment you can act *before* money moves; everything after is cleanup.
The three builds
- Validation functions: block or flag pre-payment — freight-forwarder address lists for resale-fraud categories, PO boxes on signature-required goods, promo-eligibility checks against identity clusters, quantity caps on fraud-magnet SKUs.
- Signal enrichment: capture checkout-behavior signals into order attributes — time-in-checkout (bots and card-testers move oddly fast), address-entry patterns, payment-retry counts. Each becomes screening input and dispute evidence.
- Selective friction: risky carts (first order + high value + expedited) get a confirmation step or phone-collection requirement; clean carts sail through. Friction as a scalpel, not a tax.
Pre-payment beats post-payment
Everything downstream of payment is remediation: holds, cancellations, refunds, disputes. A blocked checkout is the only intervention with zero cleanup cost — no refund latency, no rate exposure, no evidence packet.
The balance is conversion: every validation is a potential false positive taxing a real customer. Build from your own dispute post-mortems — each rule should trace to a loss pattern you've actually eaten. Aurai complements the checkout layer with post-order outcome-trained scoring — checkout rules catch the knowable-now; Prevent catches the knowable-from-history.
Frequently asked questions
Is checkout extensibility worth it for fraud alone?
If you're already on Plus, the validation functions are cheap wins built from your loss patterns. It's not a reason to upgrade by itself — post-order screening covers most of the value at any tier.
What's the best first checkout validation to build?
Whatever your last five fraud losses shared. Generic rules generate false positives; rules traced to actual loss patterns pay immediately.
Post reflects public documentation, industry surveys, and Aurai's own book of disputes as of the publish date. Visa, Mastercard, American Express, Discover, Stripe, PayPal, and Shopify are trademarks of their respective owners; Aurai is independent and not endorsed by any of them. Network rules change — always verify current official rules before acting on any specific tactic.