OFAC Rejected Transaction Glossary Part 1

What a rejected transaction is in sanctions screening, and how agents decide to block a payment.

TL;DR

TL;DR: A rejected transaction is a payment that a compliance system declines because screening flagged the counterparty. In the sanctionsai.dev flow, a flagged result maps to BLOCK, so the transaction never completes.

What a rejected transaction means

In sanctions compliance, a rejected transaction is one stopped because the counterparty appears on a sanctions list, most commonly the SDN List maintained by OFAC, the Office of Foreign Assets Control. Because OFAC enforcement is strict liability, intent is not required, so stopping the payment is the safe default when a match appears.

Why rejection happens for agent payments

Payment rails such as x402, AP2, ACP, and Coinbase AgentKit move money but do not screen the recipient. An agent that pays without screening can complete a prohibited transaction. The sanctionsai.dev API screens the counterparty before the agent pays: clean returns ALLOW and flagged returns BLOCK, in one HTTP call under 100 ms.

What to do after a rejection

Treat the rejection as a control working, not a failure. Review the match, and use dispute_open if the flag looks wrong, a false positive rather than a true hit. Keep an audit trail of the decision so it can be reconstructed later. Not documented: any guarantee of reversal outcomes for disputed rejections.