AS2 moves documents over HTTP or HTTPS between two parties’ AS2 software. Before a document leaves, it is signed with the sender’s certificate and encrypted with the receiver’s, so only the intended trading partner can read it and the trading partner can verify who sent it. The receiver returns a message disposition notification (MDN), a signed receipt confirming the file arrived intact.
Because it connects trading partners directly, AS2 avoids the per-document fees of an EDI VAN and delivers in near real time. Many large retailers and manufacturers require it for EDI. Setup involves exchanging AS2 identifiers, endpoint URLs and certificates, then testing the connection before production.
The common failures are operational: an expired or replaced certificate, a changed URL or firewall rule, or an MDN that never comes back. Any of these can stop orders or invoices quietly until someone notices. An MDN confirms delivery of the file only; the next check is the functional acknowledgment, and the business review comes after that.