OFAC screening for DeFi explained

What sanctions compliance means for decentralized finance protocols, front ends, and liquidity pools.

TL;DR

TL;DR: DeFi protocols still face OFAC exposure, especially at the front end and any treasury or operator-controlled account. Screening counterparty wallets before a transaction settles is the core control, and intent is not a defense.

The front end is the exposure point

OFAC (the Office of Foreign Assets Control) is a strict liability regime. Even when a protocol's smart contracts are permissionless, the interface that lets a user interact with them, and any funds the team controls, can create liability. If a front end routes a transaction to a blocked wallet or the protocol treasury pays one, penalties can start at $356,000 per violation.

What screening looks like in DeFi

The practical control is to check the counterparty address and its entity against the SDN List (Specially Designated Nationals and Blocked Persons List) before a transaction is submitted. The 50 Percent Rule extends the block to entities 50 percent or more owned by a blocked person, so a check that resolves the entity behind an address is more reliable than a bare address match.

Running it automatically

agentmail, the screening API at sanctionsai.dev, is designed for this: screen a counterparty before an agent or dapp pays, in one HTTP call under 100 ms, returning clean (ALLOW) or flagged (BLOCK). It checks 947 OFAC-listed crypto wallets and 19,218 SDN names across 16 jurisdictions, synced hourly, with a free tier of 5 checks per day to start.