You've been approved as a Walmart supplier — congratulations. Now comes the technical requirement that stops many vendors in their tracks: EDI compliance.
Walmart serves customers nearly 260 million times per week across more than 10,000 locations worldwide. To handle that volume, the company requires all suppliers to exchange business documents electronically using specific EDI transaction sets, formats, and timelines. There is no manual alternative. Miss a deadline, send an incorrect document structure, or fail certification testing — and your products don't ship. Worse, you'll face chargebacks that can run thousands of dollars per violation.
Here's everything you need to know about Walmart's EDI requirements in 2026, including required transaction sets, the testing process, common rejection errors, and how to get compliant fast.
Updated April 16, 2026
In this article
Why Walmart Requires EDI
Walmart mandates EDI for every supplier because manual processes — emails, paper purchase orders, phone confirmations — cannot operate at the scale and speed the company requires. EDI eliminates human data entry from the transaction flow, reduces errors, and gives Walmart real-time visibility into what's coming, when, and from whom.
For suppliers, EDI compliance isn't just a Walmart checkbox. It's a foundation for avoiding chargebacks, building a reliable supply chain reputation, and scaling your retail relationships over time. Suppliers who invest in proper EDI setup from the start spend far less time firefighting than those who cut corners early.
Required EDI Transaction Sets
Walmart uses the ANSI X12 EDI standard. Every supplier must be able to send and receive the following core transaction sets:
| Transaction Set | Document | Timing Requirement | Notes |
|---|---|---|---|
| EDI 850 | Purchase Order | Sent by Walmart; receive and process promptly | Foundation of every Walmart transaction |
| EDI 855 | Purchase Order Acknowledgment | Must be sent within 24 hours of receiving the 850 | Failure to send triggers compliance flags immediately |
| EDI 856 | Advance Ship Notice (ASN) | Must be sent before shipment arrives — typically within 30 minutes of ship | Most chargeback-prone document; must match physical shipment exactly |
| EDI 810 | Invoice | Sent after shipment, typically within 24 hours | Must reconcile with 850 and 856 or payment delays occur |
The EDI 856 Advance Ship Notice is the document that generates the most chargebacks for new Walmart suppliers. It must be transmitted before the shipment arrives, must contain accurate carton contents and SSCC labels, and must match the physical shipment exactly. Any discrepancy is a chargeback.
AS2: Walmart's Required Communication Protocol
Walmart requires all suppliers to use AS2 (Applicability Statement 2) as the communication protocol for transmitting EDI documents. AS2 sends data over the internet inside a secure "envelope" using encryption and digital certificates, providing authenticated, receipt-confirmed delivery that meets Walmart's security standards.
What this means practically:
- You need an AS2 connection configured specifically for Walmart's systems
- Both parties must exchange and validate digital certificates before going live
- Your AS2 setup must be tested and certified before you can transact
- Certificate renewals and connection monitoring are ongoing responsibilities
Managing AS2 in-house is technically demanding. Most suppliers work with an EDI provider who handles AS2 configuration, testing, and maintenance on their behalf. For a detailed comparison of AS2 versus VAN connectivity, see our guide on choosing between AS2 and an EDI VAN.
GDSN: Product Data Synchronization
In addition to transaction-level EDI, Walmart requires suppliers to participate in a Global Data Synchronization Network (GDSN). GDSN allows trading partners to share product data automatically — so when you update your product database, Walmart's systems are updated in real time.
GDSN compliance means maintaining accurate, current product records including item descriptions, dimensions, weights, GTINs, and images. Discrepancies between your GDSN data and what Walmart has on file can create downstream problems in ordering, labeling, and invoicing.
The Certification Testing Process
Before you can transact live with Walmart, you must complete a formal certification process through Walmart's Retail Link supplier portal. Here's what to expect:
Step 1: Accept the supplier agreement
After Walmart's merchandising team approves your products, you'll receive a supplier agreement through Retail Link. Review it carefully — this document establishes your compliance obligations, chargeback structure, and EDI requirements.
Step 2: Obtain your Walmart supplier number
Walmart assigns a unique supplier number that identifies you across all their systems. This number is required for EDI configuration and must be included in your transaction sets.
Step 3: Configure your AS2 connection
Work with your EDI provider to configure your AS2 connection to Walmart's specifications, exchange digital certificates, and verify connectivity before testing begins.
Step 4: Build document mappings
Your EDI system must translate Walmart's specific document formats to and from your internal systems. Each transaction set — 850, 855, 856, 810 — requires its own mapping. This is where working with an experienced EDI provider pays off, as mapping errors are the most common cause of testing failures.
Step 5: Complete certification testing
Walmart requires test transactions for each document type before going live. Testing validates that your documents are correctly formatted, contain all required fields, and meet timing requirements. Failures must be corrected and retested before you can ship.
Common Rejection Errors and Chargebacks
New Walmart suppliers most commonly run into compliance problems in the following areas:
- ASN sent after shipment arrives rather than before
- ASN contents that don't match the physical shipment — wrong quantities, missing cartons, incorrect SSCC labels
- Missing required fields in the 855 acknowledgment
- Invoice amounts that don't reconcile with the original purchase order
- Incorrect or missing GTINs on item data
- Certificate expiration causing AS2 connection failures
Each of these errors can trigger an automatic chargeback. For a deeper look at how chargebacks compound and what they actually cost your business, see our guide on EDI compliance requirements for retailers.
Walmart operates a zero-tolerance compliance policy. Unlike some retailers that allow a grace period for new suppliers, Walmart's chargeback system is largely automated. Errors trigger deductions immediately — which is why getting the setup right before go-live matters more than fixing it after.
How BOLD VAN Gets You Compliant
At BOLD VAN, we handle every technical component of Walmart EDI compliance on your behalf — at no extra charge beyond your standard service plan. Here's what's included:
- AS2 setup and configuration to Walmart's exact specifications
- Digital certificate exchange and management
- Document mapping for all required Walmart transaction sets
- Support through Walmart's certification testing process
- Ongoing AS2 monitoring, maintenance, and certificate renewals
- GDSN compliance guidance
- Real-time visibility into all transactions via the BOLD Manager portal
We've onboarded hundreds of suppliers to Walmart and other major retailers. Our team knows exactly what Walmart's testing team expects and how to get through certification without delays. For a broader look at how trading partner onboarding works across multiple retailers, see our manufacturer's guide to trading partner onboarding.
If you're selling through Walmart's online marketplace as a Drop-Ship Vendor rather than shipping to Walmart distribution centers, the EDI requirements differ significantly. See our guide to Walmart EDI for drop-ship vendors for a full breakdown of DSV-specific compliance requirements.
Ready to get started? Schedule a demo with our EDI experts or call 844-265-3777 to talk through your Walmart compliance timeline.
Frequently Asked Questions
Does Walmart require EDI for all suppliers?
Yes. Walmart requires all suppliers to be EDI-capable. There is no manual alternative for ongoing business. Suppliers must use AS2 as the communication protocol and exchange documents in the ANSI X12 format.
What EDI transaction sets does Walmart require?
Walmart requires four core EDI transaction sets: EDI 850 (Purchase Order), EDI 855 (Purchase Order Acknowledgment), EDI 856 (Advance Ship Notice), and EDI 810 (Invoice). The 856 ASN is the most chargeback-prone document — it must be sent before the shipment arrives and must match the physical shipment exactly.
What is AS2 and why does Walmart require it?
AS2 (Applicability Statement 2) is a secure protocol for transmitting EDI data over the internet using encryption and digital certificates. Walmart requires AS2 because it provides authenticated, encrypted, and receipt-confirmed delivery — a standard the company mandates for all supplier connections to protect the integrity of its supply chain data.
What is GDSN and why does Walmart require it?
GDSN (Global Data Synchronization Network) allows suppliers and retailers to share product data automatically and in real time. Walmart requires GDSN compliance so that as a supplier updates its product database, Walmart's systems are updated simultaneously — eliminating data discrepancies that can cause order errors and chargebacks.
What happens if my EDI documents don't pass Walmart's testing?
If your EDI documents fail certification testing, your products cannot ship until issues are resolved. Common failure points include incorrect document structure, missing required fields, ASN timing errors, and mismatches between the 850, 856, and 810. Working with an experienced EDI provider significantly reduces the risk of testing failures.
Can BOLD VAN handle my Walmart EDI setup?
Yes. BOLD VAN configures and maintains your AS2 connection, handles all document mapping to Walmart's specifications, manages trading partner onboarding, and supports you through certification testing — all included in your service plan at no extra charge.
