Integration
EDI 850, 855 and 856
In ANSI X12 EDI, an 850 is a purchase order, an 855 is the purchase order acknowledgement, and an 856 is the advance ship notice. Together they carry the core order cycle between trading partners as structured, machine-readable messages.
Also known as: EDI purchase order transactions, X12 850
The three transactions in sequence
Each message corresponds to a step in the order cycle.
- 850 — Purchase Order. The buyer's order: parts, quantities, prices, requested dates.
- 855 — Purchase Order Acknowledgement. The supplier's response, including any changes to date, quantity, or price.
- 856 — Advance Ship Notice (ASN). Notification that goods have shipped, typically with carrier and package detail.
- In EDIFACT the equivalents are ORDERS, ORDRSP, and DESADV.
Where EDI works, and where coverage stops
EDI is genuinely excellent within its domain. Where a trading relationship is high-volume, stable, and both parties have made the investment, EDI is faster, cleaner, and more reliable than anything conversational.
The limitation is coverage, not capability. EDI requires implementation on both sides, and for a supplier shipping a few dozen lines a year the investment never pays back. So EDI covers the top of the supply base and stops — leaving the tail on email, which is where the coordination burden then sits.
The realistic model is not EDI versus email but both: EDI for the relationships that justify it, and automation over email for everything else.
How Evolinq handles it
Evolinq covers the suppliers EDI never reached. Where EDI is already in place it should stay; Evolinq automates the email-based tail on the same terms.
Frequently asked questions
What is an EDI 850?
An EDI 850 is the ANSI X12 transaction set for a purchase order. It carries the buyer's order to the supplier as a structured, machine-readable message, including part numbers, quantities, prices, and requested dates.
What is the difference between an 855 and an 856?
An 855 is the purchase order acknowledgement — the supplier confirming the order and stating any changes to date, quantity, or price. An 856 is the advance ship notice, sent later to say the goods have actually shipped.
Why don't all suppliers use EDI?
Because EDI requires implementation and maintenance on both sides. For a supplier shipping small volumes to a given customer, the setup cost cannot be recovered. EDI therefore tends to cover high-volume relationships while the long tail of suppliers stays on email.