OFAC screening frequency requirements

How often a sanctions check should run to stay compliant as lists and counterparties change.

TL;DR

TL;DR: Screening should run at the moment of each transaction against a current list, not once at onboarding. The SDN List changes over time, so a stale check can let a newly blocked party through.

Why onboarding-only screening fails

OFAC's SDN List (Specially Designated Nationals and Blocked Persons List) is updated as new persons, entities, and wallets are designated. A counterparty that was clean at signup can become blocked later, and a counterparty can also change ownership and fall under the 50 Percent Rule after the fact. Because OFAC is strict liability, intent is not required, and a stale check offers no protection.

The right frequency: at payment time

The reliable pattern is to screen at the moment a payment is initiated, every time, using data refreshed frequently. agentmail syncs its data hourly: 947 OFAC-listed crypto wallets and 19,218 SDN names across 16 jurisdictions. A per-transaction call against hourly-synced data means the check reflects the list as it stands when the money moves.

What that costs in practice

Running a check per transaction is only practical if the call is fast and cheap. agentmail returns clean (ALLOW) or flagged (BLOCK) in one HTTP call under 100 ms, with a free tier of 5 checks per day and paid tiers up to 100,000 checks per month. That makes per-transaction, always-current screening affordable rather than a compliance luxury.