What is OFAC sanctions screening? A complete guide

Screening checks a counterparty against OFAC lists before you transact and returns a clear ALLOW or BLOCK.

TL;DR

TL;DR: OFAC sanctions screening is the process of checking a person, entity, or wallet address against the SDN List and OFAC-listed wallets before you transact, so you can block a sanctioned counterparty before value moves.

What it is

OFAC, the Office of Foreign Assets Control at the US Treasury, publishes the Specially Designated Nationals (SDN) List. Screening means comparing the identifiers of a counterparty (a name, a wallet, a jurisdiction) against that list and against OFAC-listed crypto wallets. A clean result allows the transaction; a flagged result blocks it.

Why it matters

OFAC liability is strict: intent is not required, and civil penalties start at $356,000 per violation. Under the 50 Percent Rule, an entity owned 50 percent or more by a blocked person is also blocked. Screening is the control that keeps your payment path from accidentally facilitating a sanctioned transaction.

How it works

A modern screening flow follows the 4-Gate Agent Payment Protocol: SCREEN the counterparty, SCORE the risk, STOP if flagged, and STAMP the decision into a record. sanctionsai.dev does this in one HTTP call under 100 ms, using live data of 947 listed wallets, 19,218 SDN names, and 16 jurisdictions synced hourly.

How to implement it

Start with the free tier (5 checks per day, no signup, no key), then move to Dev ($19 per month) or Pro ($99 per month) as volume grows. The MIT-licensed API is self-hostable and available as an MCP server via pip install sanctions-mcp.