Answer
What is an EDI 855 and what happens if you miss one?
Updated July 2026 · by the DynamoDocs team
The short answer
An EDI 855 is a purchase order acknowledgment: the supplier's reply to a buyer's 850, confirming line by line what will be shipped, at what price, and when. Retail partners require it inside a stated window, often 24 hours, and a late or missing 855 is a chargeback. DynamoDocs sends it automatically for orders that pass validation.
What it actually says
An 855 is not a read receipt. Each line carries a status: accepted, backordered, quantity changed, price changed, or rejected. The header summarises whether the order was taken as sent or with changes, so the buyer can plan around what is really coming.
Why a missing one costs money
Large buyers run compliance programmes that measure acknowledgment timeliness alongside fill rate and on-time delivery. A missed 855 is usually a flat chargeback per order, and the failure is invisible from the supplier's side: nothing breaks, no error appears, the order simply looks fine.
Why automatic sending needs a gate
An 855 is a commitment to prices and quantities, so it should never be generated from a document nobody has checked. DynamoDocs sends automatically only for orders that pass validation; a flagged order records what it owes and appears in a Responses owed list, and clearing the flag sends the acknowledgment.
The 997 is a different thing
A 997 functional acknowledgment says the file arrived and parsed. It does not say the order was accepted. Partners generally require both, and confusing them is a common source of compliance failures.
And the 865, when the buyer changes the order
If the buyer sends an 860 change request, the reply is an 865, not another 855. It echoes the buyer's change sequence so they can tell which revision you answered. DynamoDocs picks the right one from the document itself.
Related questions
How fast does the 855 need to go out?
It depends on the partner's guide, but 24 hours is common and some retailers require less. Automatic sending on a clean order means it goes within seconds of receipt.
What if we cannot fill the order as sent?
That is exactly what the line statuses are for. The 855 reports backorders, quantity changes, and rejections per line, which is far better for the buyer than silence.
Do we need a VAN to send it?
No. DynamoDocs delivers over SFTP, AS2, or a folder your existing VAN client watches, whichever your partner uses.
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