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Fraud rules

Fraud rules evaluate one activity and return Allow, Review or Block. They can apply to transactions, logins, sign-ups, password resets, beneficiary changes, payouts and withdrawals.

Ongoing monitoring is separate. It decides who is checked again over time and when a material change should reach your team.

Start with the rule library

Open Rules & Policies → Fraud rules → Rule library. Search or filter, then select Install.

Installation publishes version 1 for the current organisation and environment. Repeating the same installation does not create a duplicate. Disabling a rule keeps its decision history.

Test before you publish

Use Test against last 30 days before publishing a custom rule. The test does not change activities, create alerts or create charges.

Publish with control

Publishing creates an immutable version. Later edits create another version so an earlier decision always points to the exact rule that produced it.

Decision settings

Open Settings to configure review and block thresholds, money limits and advanced scoring. These settings combine matched rules into the final decision. They are not a second rule library.

API response

Read assessment.summary first:

json

{
  "assessment": {
    "summary": {
      "outcome": "review",
      "title": "Review required",
      "reason": "A high-risk transaction rule matched.",
      "score": 82,
      "riskLevel": "high",
      "matchedRules": 1,
      "nextAction": { "type": "review_activity", "label": "Review transaction" }
    }
  }
}

Use summary.outcome to branch and summary.nextAction for the next workflow step. Detailed rules, screening, billing and Travel Rule evidence remain available when you need them.

Subscribe to fraud.transaction.assessed or fraud.activity.assessed. Both return the same data.summary shape. Deduplicate by the webhook envelope id. Use your externalActivityId and externalTransactionId to correlate the result.