OFAC screening for payment aggregators

How aggregators that bundle many merchants screen each sub-merchant and transaction.

TL;DR

TL;DR: A payment aggregator must screen every sub-merchant at onboarding and each transaction at processing time. Because it settles on behalf of many merchants, the aggregator inherits each merchant's sanctions exposure.

The aggregator inherits every merchant's risk

A payment aggregator processes on behalf of many merchants, which means it sits between each of them and their customers. When any sub-merchant transacts with a blocked party, the aggregator is the party settling the payment, and OFAC is strict liability: intent is not required, and penalties start at $356,000 per violation.

Onboarding plus per-transaction checks

The control has two layers. At onboarding, screen each sub-merchant and its beneficial owners against the SDN List (Specially Designated Nationals and Blocked Persons List), applying the 50 Percent Rule to catch entities 50 percent or more owned by a blocked person. At processing time, screen the transaction counterparty, because lists change after signup.

Running both layers in one API

agentmail, the screening API at sanctionsai.dev, covers both: one HTTP call under 100 ms returns clean (ALLOW) or flagged (BLOCK), checking 947 OFAC-listed crypto wallets and 19,218 SDN names across 16 jurisdictions, synced hourly. An aggregator can call it at merchant onboarding and again per transaction, holding flagged payments for review.