BAK
Beginning segment for PO acknowledgment: acknowledgment type, the PO number and date being acknowledged.
EDI 855: Purchase Order Acknowledgment
The supplier’s answer to a purchase order: accepted, rejected, changed, or backordered, line by line. Supplier to buyer. This page covers what the 855 is for, the segments you meet when you open one, the documents it travels with, where it tends to go wrong, and how it moves over AS2 into your systems on Files.com, which receives, parses, validates, and routes it as configuration.
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What The 855 Is For
The 855 is the supplier’s business reply to an 850. Where the 997 only says the order was received and parsed, the 855 says whether the supplier will fill it: the whole order accepted as is, accepted with changes, rejected, or answered line by line with quantities confirmed, substituted, backordered, or declined and the dates the supplier can actually meet.
Buyers who require an 855 use it to update their own systems before goods move, so the receiving dock and accounts payable expect what will really arrive. A supplier that skips the 855 and ships anyway leaves the buyer matching a shipment against an unconfirmed order, which is where chargebacks start.
The Segments You Meet First
In document order, the segments that carry the 855's meaning. A partner's implementation guide says which are required and which fields each must hold.
REF
References, including the supplier’s sales order number.
DTM
Dates, typically the scheduled ship date the supplier commits to.
PO1
The line item being acknowledged, echoing the buyer’s quantity, price, and identifiers.
ACK
Line item acknowledgment: the status (accepted, backordered, rejected, changed), the quantity, and the date.
CTT
Transaction totals: the number of PO1 lines.
Where It Goes Wrong
The common mistake is acknowledging at the header only when the buyer requires line-level ACK segments, or sending an acceptance that echoes the buyer’s dates while the warehouse plans to ship later. An 855 that says one thing and an 856 that shows another is the fastest route to a compliance chargeback.
The Documents It Travels With
The 855 rarely moves alone. These are the documents that precede, answer, or settle it.
850 · Purchase Order
A buyer’s order to a supplier: the items, quantities, prices, dates, and ship-to locations.
See The 850860 · Purchase Order Change Request (Buyer Initiated)
A buyer’s change to an order already sent: add, delete, or modify lines, quantities, prices, or dates.
See The 860865 · Purchase Order Change Acknowledgment / Request (Seller Initiated)
The seller’s answer to a buyer’s change request, or a change the seller proposes on its own.
See The 865856 · Ship Notice / Manifest (ASN)
The advance ship notice: what is in the shipment, how it is packed, and how it is labeled, sent before it arrives.
See The 856997 · Functional Acknowledgment
The receipt that says an EDI transmission arrived and was parsed, with any syntax errors found.
See The 997How The 855 Moves On Files.com
A partner sends the 855 over AS2, SFTP, or FTPS, and it lands in that partner’s inbox folder on Files.com with the transport receipt recorded. From there it is a workflow, not a project: TransformScript parses the X12 natively into the JSON, CSV, or XML your ERP or WMS reads, content validation flags a document whose contents are wrong before anything ingests it, and an automation routes the result to the system and the people who act on it.
Outbound is the mirror image. Your system exports its record, TransformScript builds the 855 the partner’s guide specifies, and the file dropped in the partner’s outbox goes out over AS2 with automatic retries until the MDN confirms delivery. Every transmission in both directions is in the audit log, and delivery monitoring alerts when a 855 that was due never arrives. The full picture is on the EDI software page.
EDI 855 Questions
What teams ask about the 855 and how it moves on Files.com.
An EDI 855 is the X12 Purchase Order Acknowledgment. The supplier sends it in reply to an 850 to say whether and how the order will be filled, at the header or line by line, with the quantities and ship dates it commits to.
No. The 997 is a functional acknowledgment that says the 850 arrived and parsed. The 855 is the business answer about whether the goods will ship, on what dates, and in what quantities.
The 855 acknowledges an original 850. The 865 acknowledges a buyer’s 860 change request, or carries a change the seller initiates.
Yes. Files.com is a standards-compliant RFC 4130 AS2 endpoint, and a 855 sent by a trading partner lands in that partner’s inbox folder with a signed MDN receipt returned to the sender. Partners who exchange over SFTP or FTPS connect to the same platform and the document lands in the same place.
Yes. TransformScript parses the X12 855 natively and writes the JSON, CSV, or XML your systems ingest, as a step in the workflow that fires when the document arrives. Outbound, the same engine builds a 855 from your system’s export and drops it in the partner’s outbox for delivery.
Exchange The 855 Without The Legacy Stack
Start the 7-day trial, turn AS2 on, and exchange certificates with your partner. The 855 lands in their folder, parses into the record your system reads, and every transmission carries a signed receipt.
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