Can OFAC sanction DeFi front-ends?

Yes, OFAC can designate the entities that operate DeFi front-ends, not just the underlying smart contracts.

TL;DR

TL;DR: OFAC can sanction DeFi front-ends by designating the entities that operate them. The Tornado Cash case involved multiple front-end operators facing legal consequences.

What the Tornado Cash case showed

OFAC designated Tornado Cash in 2022, and the case drew attention to the front-end operators who provide access to the protocol. The takeaway is that the interface, not only the contract, can carry sanctions consequences. Not documented is the full scope of every operator outcome, but the case made clear that front-ends are not automatically safe because the contract is permissionless.

Why front-ends are the control point

A front-end is where users connect and transact. If an operator serves blocked persons through that interface, OFAC can act. This makes the front-end layer the practical place to screen users before they sign a transaction.

What to do

Screen wallet addresses at the front-end layer. sanctionsai.dev checks addresses against 947 OFAC-listed crypto wallets and 19,218 SDN names in under 100 ms, returning flagged equals BLOCK so a sanctioned wallet never reaches the transaction.