EDI 850 — the ANSI X12 purchase order document explained
In short: EDI 850 is the ANSI X12 transaction set for a purchase order — the standard message a buyer sends to a supplier to initiate an order in the US retail and B2B ecosystem. This guide covers the EDI 850 structure, mandatory segments, common variations by retailer (Walmart, Target, Amazon), and how it maps to EDIFACT ORDERS in Europe.
Key capabilities
- Message purpose: The 850 is the buyer's formal purchase order — the trigger document for the entire order-to-cash cycle.
- Header segments: BEG (beginning), REF (references, PO number), DTM (dates), N1 (trading parties: ship-to, bill-to).
- Line item segments: PO1 (item detail: qty, unit, price, UPC/GTIN), CTP (contract terms per line), PID (product description).
- Retailer variations: Walmart, Target, Amazon, Costco each have their own 850 flavor with additional required segments and codes.
- Acknowledgment (997): The 997 functional ack confirms receipt of the 850; the 855 (PO ack) confirms the supplier's response to the order.
- EDIFACT equivalent: In Europe, the EDIFACT ORDERS message plays the same role as the X12 850, with a different segment structure.
EDI 850 in a typical retail supply chain
Walmart's replenishment system detects low stock on SKU X at DC 3. It generates a purchase order to supplier Y in the ERP. The ERP outputs an X12 850 with the SKU, quantity, ship-to DC address, ship-by date, and pricing per contract. The 850 goes via AS2 to supplier Y.
Supplier Y's EDI system receives, acks (997), translates to ERP format, posts as sales order. Warehouse picks and packs. When goods leave, an 856 (ASN) is sent to Walmart with SSCC pallet labels. When goods are received, Walmart's system reconciles the ASN and pays the associated 810 (invoice) per contract terms.
Frequently asked questions
What is EDI 850?
EDI 850 is the ANSI ASC X12 transaction set for a purchase order. It's the message a buyer sends to a supplier through EDI to place an order. It includes buyer/seller identification, ship-to and bill-to addresses, PO number, line items with quantities and prices, and delivery instructions.
What is the EDI 850 format?
An EDI 850 is a hierarchical structure of segments and elements. Envelope: ISA/GS/ST … SE/GE/IEA. Header: BEG, REF, DTM, N1 loops. Detail: PO1 loops with CTP, PID, SCH. Summary: CTT with totals. Each segment is a delimited string of elements, terminated by a segment terminator (~).
What is the difference between EDI 850 and EDI 856?
The 850 is a purchase order (buyer → seller), placing the order. The 856 is an advance ship notice (seller → buyer), telling the buyer what's shipping, when, and how it's packed. Together with the 810 (invoice) they form the core X12 order-to-cash triplet.
What is the EDIFACT equivalent of EDI 850?
The EDIFACT equivalent of X12 850 is the ORDERS message. Both play the role of a purchase order, but the segment structures differ (BEG → BGM, PO1 → LIN, etc.). A modern EDI platform translates between the two automatically.
How is EDI 850 processed?
Received via AS2 (or VAN), the 850 is validated (envelope, structure, business rules), a 997 ack is sent back, then the message is translated to the supplier's ERP format and posted as a sales order. The supplier's ERP generates an 855 (PO ack) which is translated back to X12 and sent to the buyer.