Walmart EDI Requirements for New Suppliers: A Complete Checklist

Getting EDI-compliant with Walmart is a rite of passage for any supplier. The process is well-documented but has enough moving parts that first-timers routinely delay their go-live by weeks. Here’s what you actually need to know.

What Walmart Requires

Walmart uses X12 EDI standards and requires all suppliers to exchange transactions through their Retail Link portal and EDI network. The core transaction sets are:

• 850 — Purchase Order (Walmart sends to you)
• 855 — Purchase Order Acknowledgment (you send back)
• 856 — Ship Notice / ASN (you send when you ship)
• 810 — Invoice (you send after shipment)
• 997 — Functional Acknowledgment (sent by both sides)

Some suppliers also need the 820 (Payment Remittance) and 846 (Inventory Inquiry).

The ISA IDs

Every EDI transaction has an ISA (Interchange Control Header) envelope. Walmart’s ISA IDs are well-known but still trip people up:

• ISA06 (Sender ID): Your company’s EDI ID, issued when you register
• ISA08 (Receiver ID): Walmart’s — typically 008930330 for 2-day shipments

Get the wrong ISA ID and your transactions will be rejected before they’re even read.

Connection Methods

Walmart accepts EDI via:

• VAN (Value Added Network): The traditional route. Walmart has approved VANs — you set up an account, connect through them. Slower and more expensive but very reliable.
• AS2: Direct, certificate-based transport over HTTPS. Faster and cheaper at scale, but AS2 cert setup adds complexity upfront.

Most small suppliers start with a VAN and migrate to AS2 once volume justifies it.

The Certification Process

Before you can go live, Walmart requires you to pass transaction testing:

1. Register in Retail Link — your buyer sets this up
2. Obtain your Supplier ID and EDI IDs from Walmart’s EDI team
3. Configure your mapping — set up 850 inbound, 855/856/810 outbound
4. Submit test transactions through Retail Link’s EDI testing portal
5. Get certification sign-off from Walmart’s EDI team

The certification portal is straightforward, but the coordination between your buyer, Walmart’s EDI team, and your own IT takes time. Budget 3–6 weeks for the full process.

The 856 Is the Hard Part

The Ship Notice (856) is where most suppliers get stuck. Walmart’s 856 spec has strict requirements on:

• Loop hierarchy — CTT > HL > LIN > SN1 nesting must be exact
• Carton-level detail — each carton needs its own HL loop
• PRD and TD1 segments — dimensions and weight, or you’ll get chargebacks
• UCC-128 label correlation — the SSCC-18 on your label must match the 856

Walmart’s chargeback program is real. A bad 856 costs you money, not just time.

Common Mistakes

• Wrong qualifier on BEG03 — Purchase Order Number segment qualifier must be SA
• Missing DTM segments — Ship date and delivery date are required
• ISA05/ISA07 qualifiers wrong — typically 01 for DUNS, ZZ for mutually defined
• Functional Group IDs not matching — GS02/GS03 must match your ISA IDs

Get Help If You Need It

Walmart’s EDI spec documents are thorough but dense. If you’re spending more than a week trying to get test transactions to pass, it’s time to bring in someone who’s done it before.

TebcoForge specializes in exactly this. We’ve handled Walmart supplier onboarding dozens of times. Get a quote and we’ll tell you how long it’ll take.