Purchase Order Acknowledgment
The EDI 855 Purchase Order Acknowledgment is a supplier’s structured response to an EDI 850, confirming, rejecting, or modifying each line of the purchase order before anything ships.
What is EDI 855?
The EDI 855 is the ANSI X12 Purchase Order Acknowledgment transaction set. A supplier sends it in response to an EDI 850 to confirm the order was received and to state, line by line, what will actually ship, what is backordered, and what has changed.
The 855 is the supplier’s commitment. Where a 997 Functional Acknowledgment only says "your file arrived and parsed," the 855 is a business-level answer: line one accepted as ordered, line two backordered until the 22nd, line three price-corrected. Buyers use it to catch problems while there is still time to react, and many retailers score suppliers on 855 timeliness the same way brokers score carriers on tender response. It plays the same role in the order cycle that the EDI 990 plays in the freight cycle: the structured yes or no that lets the sender stop waiting and start planning.
Key segments
What's inside an EDI 855.
Example
A sample EDI 855 message.
ST*855*0001~BAK*00*AC*4501776*20260806~REF*VN*S-88213~N1*SE*Pacific Supply Co*92*SUP221~PO1*1*48*CA*18.50**VN*PS-4416~ACK*IA*48*CA~PO1*2*120*EA*2.10**VN*PS-2210~ACK*IB*120*EA~CTT*2~SE*10*0001~
Illustrative values in X12 format (segment terminator ~, element separator *) showing the common segments of a 855. Each trading partner's spec defines its own required segments and qualifiers.
Frequently asked
EDI 855 questions, answered.
What is an EDI 855?
The EDI 855 is the X12 Purchase Order Acknowledgment. Suppliers send it after receiving an EDI 850 to confirm the order and state exactly what will ship, flagging accepted, changed, backordered, or rejected lines before fulfillment starts.
What is the difference between an EDI 855 and an EDI 997?
The 997 is a technical receipt: it confirms an EDI file was received and structurally valid, and says nothing about the business content. The 855 is the business answer: whether the supplier will fulfill the order and on what terms. Most trading relationships use both, a 997 within minutes and an 855 within hours.
When is a supplier required to send an 855?
Trading partner agreements set the window, commonly within 24 hours of receiving the 850. Large retailers enforce it through vendor scorecards and chargebacks, so an automated 855 is usually one of the first transactions suppliers stand up.
What do the ACK codes in an 855 mean?
The ACK segment carries a status code per line item: IA means item accepted, IB backordered, IC accepted with changes, IR rejected. Paired quantities and dates spell out how much will ship and when, which is what lets buyers replan around shortages automatically.
Is the 855 used in freight and logistics?
Indirectly but importantly. The 855 tells everyone downstream whether goods will actually move. A backordered line on an 855 is what prevents a wasted truck: transportation planning, the EDI 940 to the warehouse, and the EDI 204 tender to the carrier all key off what the 855 committed.
Melrose maintains full segment-level specs for the core freight set (204, 990, 214, 210) and stands up new transaction sets like the 855 on request. See the partner network or book a demo.
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