OFAC sanctions compliance for validators

What node operators and validators need to know about sanctions exposure and the screening they can add.

TL;DR

TL;DR: Validators who order or produce blocks may process sanctioned transactions. A screening check before relaying or building on a flagged transaction reduces that exposure.

Why validators have exposure

Validators and node operators touch many transactions they do not originate. OFAC strict liability does not require intent, and civil penalties start at $356,000 per violation. Processing a transaction that benefits a party on the SDN List can create exposure, so operators need a way to check before acting on a transaction.

What screening can do

sanctionsai.dev screens a counterparty in one HTTP call under 100 ms and returns ALLOW or BLOCK. An operator can check the addresses involved against 947 OFAC-listed crypto wallets and 19,218 SDN names before including a transaction in a block or relaying it. The 50 Percent Rule also applies: entities owned 50 percent or more by a blocked person are blocked.

Practical controls

Wire the check into the block-building or relaying path. A BLOCK result stops the transaction before it is acted on, and risk_score flags borderline cases for manual review. Because the data set is synced hourly across 16 jurisdictions, the check reflects the latest list without the operator maintaining it manually.