What it really takes to onboard a Walmart EDI connection

Everything starts in the supplier portal, Retail Link and the newer Supplier One that is taking over parts of it, where the agreement, the vendor number, the EDI registration and the routing guide live. You need a vendor number, the GS1 company prefix behind your item identifiers and your SSCCs, and a clear answer to which Walmart business you are shipping into: stores and distribution centres, the marketplace, or drop-ship, because each has its own document set and its own compliance program.

Download the routing guide and the EDI implementation guides for your business type at this stage, not later. Both are long and both change, and the version in the portal on the day you test is the one you are held to.

Walmart exchanges EDI over AS2. Each file goes straight between the two endpoints over HTTPS, signed and encrypted with certificates on both sides, and comes back acknowledged by a signed receipt, the MDN. That means an endpoint of your own or a provider's, certificates that will expire and need renewing, and a connectivity test with Walmart's EDI team before any document testing can begin. A smaller supplier can still put a VAN in between; the trade is a per-document fee against not running the endpoint yourself.

The exact set depends on the business you are in, and the implementation guides in the portal decide it. A supplier shipping to stores and distribution centres should expect the purchase order (850), the acknowledgement (855) where the program requires one, the advance ship notice (856), the invoice (810), the remittance advice (820), the application advice (824), and the functional acknowledgement (997) in both directions. Point-of-sale and inventory data come as separate documents to suppliers set up for them, and the marketplace and drop-ship programs run their own flows, inventory advice included.

Each one is tested on its own, and each has fields Walmart treats as required that the X12 standard calls optional. The 824 deserves particular attention: it is how Walmart says an ASN or an invoice that was syntactically fine was rejected anyway, with the reason, and a supplier whose system drops 824s on the floor learns about them through deductions.

Testing runs in Walmart's self-service test portal, document by document, until each one passes: you submit, the portal or the EDI team reports what failed, you fix it and submit again. The cycle is bounded on their side. A supplier who stalls for long enough is dropped from onboarding and has to register again, so testing is not something to start before the mapping is ready.

Three things eat the weeks. Test data: the test orders have to be processed through your real systems, so the items, the ship-tos and the carrier codes must exist there first. The ASN hierarchy: the pallet and carton structure and the SSCCs are checked against the label spec, so the ASN cannot be tested without labels. And people: every resubmission waits for someone to review it, on both sides.

The GS1-128 label on every carton and pallet carries the SSCC the ASN declares, and the receiving dock scans one to find the other. Format, placement and print quality are specified in the routing guide, and a label that does not scan is a compliance failure with the goods perfectly correct. Print a sample set, scan them with a handheld, and send the ASN that references them; if any link in that chain is manual, it will fail at volume.

Walmart scores when the ASN arrives relative to the shipment, and scores delivery against a must-arrive-by date, with early as much a miss as late. The program that measures that, on-time in-full, and the quality program that measures ASN and purchase-order accuracy, are published in the portal with their current thresholds and their current charges. Do not take those numbers from a blog, this one included: read the current version there, because they change.

1. Register in the portal, confirm the vendor number, the business type and the GS1 prefix, and download the current routing guide and implementation guides
2. Stand up the AS2 endpoint or the provider, exchange certificates, and pass the connectivity test
3. Map the inbound 850 first and prove it lands in your system as an order with the right items and ship-tos
4. Build the outbound 856 from packing records with real SSCCs, print the labels, scan them, and test the ASN and the labels together
5. Map the 810 from the shipment and the 855 where required, and route the 824 and the 997 to a person, not a folder
6. Run the test cycle to completion, then ship the first live orders with someone watching each document go out and each acknowledgement come back

That is the onboarding the EDI integration page describes in four steps, and the onboarding row of our logistics page is where it gets done, for a supplier or for the 3PL packing its orders. If a 3PL does the packing, the 940 and 945 between the two of you have to be in place first; the 940 and 945 guide covers that pair.