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Fraud Fundamentals

TL;DR
  • Pick tools and write rules later. First understand what's driving every fraud decision you make
  • Two pages here: Economics of Fraud for what fraud really costs, and Risk Appetite for how tight to set the rules
  • The core trade-off never changes. Block more fraud or block fewer good customers. You don't get both
  • Read this before you spend money on a fraud tool

Pick tools and write rules later. First understand what's driving every fraud decision you'll make. These two pages cover the why.

What You'll Learn

PageWhat It CoversRead This If...
Economics of FraudThe true cost of fraud (direct losses, false positives, operational costs, customer impact)You need to justify fraud prevention spend or understand why blocking too much is also expensive
Risk AppetiteHow to balance fraud loss tolerance, customer friction, conversion targets, and regulatory requirementsYou're deciding how aggressive your fraud rules should be or where to set your score thresholds

The Core Trade-off

Every fraud decision is the same trade-off. Block more fraud or block fewer good customers. Tighten your rules and you catch more fraud. You also reject more real sales. Loosen them and you approve more revenue and eat more losses.

The right balance depends on your business. A $5 digital good isn't a $500 physical product. A business at a 0.1% fraud rate doesn't choose like one at 1.5%.

These two pages get you there:

  1. Start with Economics and learn what fraud actually costs. It's more than the transaction amount.
  2. Then read Risk Appetite and set your thresholds against your own business model.

Key Principles

  1. Not all fraud is created equal - first-party abuse and third-party fraud need different responses.
  2. Prevention has costs too - false positives cost you revenue and customers. See Economics.
  3. Speed matters - early detection limits losses, so read the Detection Framework.
  4. Data is your weapon - invest in device fingerprinting, velocity rules, and evidence collection.
  5. 3DS is your friend - 3D Secure shifts liability for stolen card fraud to the issuer.