ASN (Advance Ship Notice)
An ASN (Advance Ship Notice), sent electronically as EDI 856 under the ASC X12 standard, is a document a supplier transmits to a buyer before a shipment arrives, describing what shipped, how it is packed, which carrier is moving it, and how it maps back to the original purchase order. It lets the receiving warehouse pre-stage labor and dock space, reconcile the shipment against the PO on arrival, and — where each carton or pallet carries an SSCC — scan a single barcode to receive an entire shipment instead of counting units by hand.
What an ASN contains
An ASN is structured, not a shipping label or a free-text email. Under EDI 856, it typically carries: the purchase order number(s) it fulfills, the ship date and expected delivery date, carrier and tracking information (SCAC code, pro number), the packing hierarchy (which items are in which carton, which cartons are on which pallet), item-level detail (part number, quantity, unit of measure) for each pack level, and — critically — the SSCC (Serial Shipping Container Code) assigned to each shippable unit.
The packing hierarchy is what makes an ASN useful rather than redundant with the PO: the PO says what was ordered, the ASN says how it was actually packed and shipped, which frequently differs from the order (split shipments, partial fulfillment, substituted pack configurations).
Why retailers and distributors require it
For a receiving dock, an ASN converts an unknown truck arrival into a planned event. Warehouse management systems use the ASN to schedule dock appointments, allocate labor, and pre-stage put-away locations before the truck backs in. On arrival, a worker scans the SSCC on each pallet or carton and the WMS pulls the full contents from the ASN data already on file — no manual counting or line-by-line entry against the PO.
This is also why ASN compliance is one of the most commonly chargeback-triggering requirements in retail vendor routing guides: a missing, late, or inaccurate ASN (wrong quantities, wrong carton count, SSCC that doesn't scan) breaks the receiving automation it exists to enable, and most major retailers penalize it accordingly.
ASN accuracy depends on upstream product and packaging data
An ASN can only be as accurate as the data feeding it. The item quantities per carton trace back to case pack quantity data held in the PIM or ERP; the SSCC assignment depends on correctly configured GS1 Company Prefix and serialization logic; the part numbers need to match what the buyer's system expects, which is the same identifier cross-reference problem that shows up in flat file uploads and EDI 850 purchase orders generally.
A supplier whose case pack quantities are wrong in its own system will generate a technically well-formed ASN that still fails on arrival, because the carton the warehouse scans doesn't contain what the ASN says it does.
Frequently asked questions
What EDI transaction set is an ASN?
An ASN is transmitted as EDI 856 (Ship Notice/Manifest) under the ASC X12 standard in North America; the EDIFACT equivalent is the DESADV message. Both convey the same core content — what shipped, how it's packed, and how it maps to the originating order.
Why did my retailer chargeback me for an ASN issue?
ASN compliance is a standard line item in most major retailers' vendor routing guides, because a missing, late, or inaccurate ASN breaks the automated receiving process it's meant to enable — the warehouse can't pre-stage labor or scan-receive a shipment without accurate advance data. Retailers commonly issue chargebacks for late ASNs, ASNs that don't match the actual shipment contents, or missing SSCC labels.
What is the difference between a PO and an ASN?
A purchase order (EDI 850) is the buyer's request for goods, sent before fulfillment. An ASN (EDI 856) is the supplier's confirmation of what actually shipped, sent after the order is picked and packed but before it arrives. The two frequently differ — split shipments, backorders, and pack-configuration substitutions mean the ASN's contents don't always match the PO line for line.
Do I need SSCC labels to send an ASN?
You can send an ASN without SSCC-labeled cartons, but you lose most of the operational benefit. The SSCC is what lets a receiving warehouse scan one barcode per carton or pallet and pull the full contents from the ASN on file. Without it, receiving staff typically fall back to manual counting against the ASN's line items, which is the slow process ASNs exist to eliminate.