Walmart EDI requirements for suppliers

What Walmart requires from a supplier

Walmart's supplier page lists six requirements in one sentence: a federal tax ID number, a minimum of $5M in liability insurance, a Dun & Bradstreet number, the ability to submit products for third-party testing, Electronic Data Interchange (EDI) and a GS1 membership number. EDI is a condition of doing business, in the same list as the insurance.

The public specification covers one program in full: drop-ship vendors (DSV), suppliers that sell under Walmart's name, hold the goods in their own warehouse and ship to the customer or to a store. Walmart's developer portal carries a guide per transaction set, all in X12 version 004010. For suppliers of stores and distribution centers the public pages hold no transaction set guides, so the set, version and label rules of those programs are not listed here.

What follows is checked against Walmart's EDI interface documentation on 3 October 2026. It is one of the trading-partner specifications we build an EDI integration against.

The eight documents in the drop-ship set

The directions of the 879 and the 824 are read from the sender IDs in Walmart's samples; the file naming list on the same page covers only the other six. The 850 is a consumer order: it carries the customer's name and address in N1*ST, the shipping method the customer chose (ND next day air, SE second day, SG standard ground) and, for a Site to Store order, the store number.

Four connection types, and the file name over SFTP

Walmart names four connection types for the drop-ship interface.

Two of the four are direct, so a network subscription is not a precondition. AS2 and SFTP need an endpoint that is reachable, monitored and tested with Walmart. A VAN moves the same files through a mailbox.

Over SFTP the file name is part of the specification:

WMI_850PO_VVVVVVVVV_YYYYMMDD_HHMMSS_NNNNNN.edi   from Walmart
WMI_860PC_VVVVVVVVV_YYYYMMDD_HHMMSS_NNNNNN.edi   from Walmart
WMI_855PR_VVVVVVVVV_YYYYMMDD_HHMMSS_NNNNNN.edi   to Walmart
WMI_856SH_VVVVVVVVV_YYYYMMDD_HHMMSS_NNNNNN.edi   to Walmart
WMI_846IB_WWWWWWWWW_YYYYMMDD_HHMMSS_NNNNNN.edi   to Walmart
WMI_997FA_VVVVVVVVV_YYYYMMDD_HHMMSS_NNNNNN.edi   both ways

VVVVVVVVV is the DSV ID Walmart assigns. The 846 uses WWWWWWWWW, the DSV ID or the facility ID, because inventory is reported per ship point. Date and time are the file creation moment in GMT, and NNNNNN is a six-digit random number. A ship notice created at 09:15:00 Eastern Daylight Time on 3 October 2026 is 4 hours behind GMT, so its name is WMI_856SH_123456789_20261003_131500_482917.edi. The delimiters are fixed as well: ~ ends a segment, * separates elements and > separates components.

Where Walmart's 855 and 856 leave the standard

The example order used across our document pages, PO 4500018236 with 24 units on line 1 and 16 on line 2, shows the differences. Under a typical retail guide the supplier confirms 12 of the 16 with a quantity-change code. Walmart's 855 has no such code: ACK02 "must not be zero" and must equal the PO102 quantity of the 850, so a line is accepted or rejected whole.

ST*855*0001~
BAK*00*NA*4500018236*20260928~
PO1*1*****PL*1~
ACK*IA*24*EA~
PO1*2*****PL*2~
ACK*R4*16*EA~
CTT*2~
SE*8*0001~

Seven ACK01 codes are in the guide: IA accepted, ID deleted, IH on hold (not used), R1 discontinued, R2 unrecognized item, R4 not available, and AR accepted and released for shipment. AR is a second status after IA; both may travel in one file, with IA first. After AR the customer can no longer cancel the line on the website. CTT01 is 2 because there are 2 PO1 segments, and SE01 is 8.

The 856 has three levels instead of four. There is no shipment level and no BSN05: the order level is the top, with 0 as its parent.

ST*856*0001~
BSN*00*4821*20261003*0915~
DTM*011*20261003*0915*ED~
HL*1*0*O~
PRF*4500018236******DS~
HL*2*1*P~
TD1******G*18.4*LB~
TD5*O*94*20~
MAN*CP*794644790132~
MAN*SM*482101~
SAC*N*G821******0****06~
HL*3*2*I~
LIN*1*PL*1~
SN1*1*24*EA~
CTT*3~
SE*16*0001~

The item is identified by the PO line number (LIN02 PL, LIN03 from PO101 of the 850), not by a UPC. TD503 holds Walmart's own carrier method code, here 20 for FedEx Ground. SAC with G821, the shipping cost, is mandatory at pack level even when the rate is 0. CTT01 counts 3 HL segments, and from ST to SE there are 16 segments. A mapping built for a retailer that wants shipment, order, pack, item and a UPC in LIN fails every one of these checks, which is why EDI mapping is done per partner.

The 846: on-hand quantity and availability codes

The inventory advice reports QTY*17, quantity on hand, per item, with the UPC, the vendor item number and the Walmart.com item number in one LIN segment. Next to the quantity each line carries an availability code in REF*ZZ and the minimum and maximum days to ship in MEA.

NA and DT remove the item from the Walmart.com catalog. Walmart asks for at least two consecutive updates with the code before the UPC is taken out of the feed. An item that disappears from the file without that step is the case the guide is written to prevent: absence is not a zero. The quantity itself is a decision about which stock counts, since on hand in the warehouse is not the same as free to sell on a second channel.

Labels, tracking numbers and GS1

The GS1 requirement on the supplier list is a GS1 Company Prefix: Walmart requires it on the application documents, and it is the source of the GTINs in the item file. In the drop-ship 856 the package identifiers are:

• MAN*CP: the tracking number assigned by the carrier, required for every package.
• MAN*SM: a unique package ID assigned by the supplier, required for every package. It may equal the tracking number.
• MAN*GM: a vendor-assigned 20-digit SSCC-18 number, for Site to Store packages only.

The 20 digits are the application identifier 00 followed by the 18-digit SSCC, built from the same company prefix. How the number is composed is on the SSCC label page.

What goes wrong

The failures below follow from rules in Walmart's guides.

• A partial quantity in ACK02. 12 of 16 confirmed is not expressible. The line goes out as IA for 16 or R4 for 16.
• AR before IA. The release status is only valid after the acceptance.
• MAN*GM on a Site to Home package, or a Site to Store package without it.
• A local time in the file name. The name uses GMT; DTM04 inside the 856 states its own time zone code.
• An item dropped from the 846 instead of reported as NA or DT twice.
• A test flag in production. Walmart's own 860 and 824 samples carry T in ISA15; production files carry P.

Errors in content come back in the 824. TED01 is 024, TED02 holds a message that can be truncated at 60 characters, and NTE holds the detail in the form ORN=12635837 LINENO=1, split over several NTE segments above 80 characters. The integration has to read the NTE, not the truncated message, to find the order line. We found no penalty amount for drop-ship or store suppliers on a public Walmart page, so none is printed here; what retailers publish is collected under EDI compliance.

Handling Walmart orders on the ERP side

Each 850 becomes a sales order with the customer's ship-to address, the Walmart PO number and the line numbers that the 855 and 856 have to return. The ERP decides per line whether stock is available, the warehouse reports the package and its tracking number, and stock per ship point feeds the 846. NetSuite, Business Central and the store platforms hold those records and have no X12 translator, so the files are built outside them. For a Shopify store the route is described under Shopify EDI integration.

We build that part to Walmart's guides and to your systems: the 850 is picked up, checked and answered with a 997, the order is created through the ERP's API, the two 855 statuses and the 856 are sent with their counts validated, and every 824 is matched to its order line and shown in the dashboard with the reason. A resend of the same PO is recognized and does not create a second order. Tell us which Walmart program you supply.