The EDI 855 Purchase Order Acknowledgment is the seller's response to an inbound EDI 850 purchase order, communicating one of three things at the line-item level: the order is accepted as submitted, accepted with changes the buyer needs to know about, or rejected. It's the supplier's earliest chance to flag price discrepancies, stock issues and wrong item numbers — before they become shipments, disputes and chargebacks. Major retailers enforce response windows, some as short as 30 minutes.
Trying to figure out what a partner's 855 spec actually wants from you? Ask us — implementation guides are our native language. Start a conversation.
When a retailer sends you a purchase order via EDI 850, the clock starts immediately. The 855 is how you confirm receipt and — more importantly — communicate what you can actually fulfill. It's tempting to treat it as a formality, an electronic "got it." It isn't. The 855 is the one document in the order cycle where problems are still free to fix: after it, every uncaught issue ships, invoices and turns into a deduction.
In this article
The Three Responses an 855 Can Give
| Response Type | What It Means | What the Buyer Does Next |
|---|---|---|
| Accepted as-is | The PO can be fulfilled exactly as submitted — quantities, prices, dates and items all confirmed | Nothing — the order proceeds to fulfillment on the confirmed terms |
| Accepted with changes | Partial or modified fulfillment — specific lines adjusted for quantity, date, substitution or backorder status | Reviews the changes, updates their systems, and confirms or pushes back on the modified terms |
| Rejected | Specific lines or the entire PO cannot be fulfilled | Sources from an alternate supplier or modifies and resubmits the order |
Each response is expressed through specific acknowledgment codes — BAK02 at the header level, ACK01 at the line level — and most retailers accept only a subset of the valid codes. For the full code reference and worked examples, see our guide to EDI 855 acknowledgment codes.
What an EDI 855 Must Include
The 855 has to carry enough detail for the buyer's system to update the right purchase order record automatically, with no human lookup. That means:
- PO number, date and product information — the reference identifiers tying the 855 back to the specific 850 it answers
- Ship and delivery dates — the seller's confirmation of when the order ships and arrives, or the revised date when the requested one can't be met
- Delivery location — the distribution center or store the shipment is routed to
- Product identifiers — UPC, EAN or partner-specific item codes confirming the right products are being acknowledged; a mismatch here is where wrong-item shipments are born
- Quantities accepted per line — which may differ from the ordered quantity under partial availability, backorders or minimum order constraints
- Expected charges — the confirmed price per accepted line, which must match the buyer's contract records or the 810 invoice will be disputed later
Every element has to match the buyer's records precisely. The 855 isn't just answering "can you fulfill?" — it's establishing the data both sides will reconcile the ASN and invoice against.
The Issues an 855 Catches Before They Cost Money
Six problem categories get resolved cheaply in the 855 or expensively downstream:
- Delivery date changes. Communicated now, the buyer adjusts receiving schedules and safety stock. Discovered later, it's a missed delivery.
- Wrong product identifiers on the PO. Flagged now, corrected in a message. Shipped wrong, it's a return, a replacement and a chargeback.
- Price discrepancies. Surfaced now, resolved before anyone invoices. Surfaced at the 810, it's an automatic deduction and a dispute cycle.
- Out-of-stock items. Removed from the acknowledged order now — instead of accepted, unshipped and penalized as a short-ship.
- Backorders. A revised availability date lets the buyer choose: wait, or source elsewhere — before the ship date, not after it.
- Discontinued items. Removed now, so the buyer stops planning inventory around a product that will never arrive.
That's the whole economic argument for taking the 855 seriously in one sentence: a discrepancy caught in the acknowledgment costs nothing, and the same discrepancy caught anywhere later costs staff time plus the deduction.
Timing Windows: Why Retailers Enforce Them
Retailers enforce 855 response windows because a late acknowledgment means late visibility into every issue above — and problems grow more expensive by the hour. The windows vary widely: most major retailers, including Walmart, Kroger, Costco and Home Depot, require a response within 24 to 48 hours of PO receipt. Target is the famous outlier at 30 minutes — one of the most demanding timing requirements in retail EDI.
Missing windows isn't a slap on the wrist. It generates automatic compliance penalties, drags down the vendor scorecard ratings that determine future order allocation, and in severe cases gets orders canceled. Which leads to the practical conclusion: tight windows can't be met by a person watching an inbox. Automated 855 generation — validating each PO line against contract records and inventory the moment the 850 arrives, and transmitting without manual review for standard acceptances — is the only approach that holds up at 2 a.m., during peak season, and on the day the order clerk is out sick.
Got a partner whose 855s keep bouncing in testing, or a Target window you're not sure you can hit? Tell us what's happening — this is exactly the kind of problem we enjoy untangling, and asking costs nothing. Send us the details.
Whether it's Target's 30-minute window or any other partner's spec, we handle 855 generation, timing compliance and mapping updates as part of flat per-partner pricing — and after more than 25 years, acknowledgment logic is still a conversation we genuinely enjoy. No demo required.
Let's talk 855sFrequently Asked Questions
What is the difference between an EDI 850 and an EDI 855?
The EDI 850 is the purchase order sent from buyer to seller — the buyer's request for specific products at specific quantities, prices and delivery dates. The EDI 855 is the acknowledgment the seller sends back: the actual commitment to fulfill, including any changes, exceptions or rejections at the line-item level. The 850 initiates the transaction; the 855 confirms what will really happen.
What happens if a supplier misses the EDI 855 timing requirement?
Missing a retailer's 855 window typically triggers automatic compliance penalties — financial deductions, vendor scorecard hits, or in severe cases order cancellation, depending on the retailer's compliance program. For retailers with tight windows like Target's 30 minutes, repeated failures can affect preferred supplier status and future order allocation. Automated 855 generation that responds without manual intervention is the only approach that consistently meets tight windows.
Does every trading partner require an EDI 855?
No — requirements vary by retailer, distributor and industry. But most major big-box retailers (Walmart, Target, Kroger, Costco, Home Depot) include the 855 as a standard requirement in their vendor EDI compliance programs. Each retailer's implementation guide documents the required data elements, timing window and response format.
How does the EDI 855 prevent chargebacks?
By surfacing order issues — price discrepancies, quantity mismatches, wrong product identifiers, backorders — before fulfillment begins instead of after a non-compliant shipment ships. A price discrepancy flagged in the 855 costs nothing to resolve; the same discrepancy discovered when the buyer's AP system processes the 810 invoice becomes an automatic deduction plus hours of dispute research.
