What Is a 3PL? Third-Party Logistics and EDI Explained

What Is a 3PL (Third-Party Logistics Provider)?

A 3PL, or third-party logistics provider, is an outsourced partner that handles warehousing, fulfillment, transportation, and distribution on behalf of a brand or manufacturer. Instead of operating your own warehouse and shipping operation, you ship inventory to the 3PL, and they pick, pack, label, and ship orders to your customers or to retail distribution centers. Common examples include ShipBob, ShipMonk, DHL Supply Chain, GEODIS, NFI, Ryder, XPO, and Amazon FBA. The 3PL becomes an extension of your supply chain - which means their systems and yours have to talk to each other in real time, and that is almost always done with EDI.

What Does a 3PL Actually Do?

Modern 3PLs go far beyond storage. A typical full-service 3PL handles the entire post-purchase supply chain so the brand can focus on sales, product, and marketing.

• Receiving inbound inventory from manufacturers and overseas containers.
• Storing inventory in racked, bin, or pallet locations inside a WMS.
• Picking and packing direct-to-consumer (DTC) orders from Shopify, Amazon, TikTok Shop, and other channels.
• Generating compliant retail shipments to Walmart, Target, Costco, Kroger, Home Depot, and other big-box DCs.
• Printing carrier labels, UCC-128 pallet labels, and routing per retailer compliance guides.
• Returns processing, kitting, light assembly, and value-added services.
• Sending real-time inventory, receipt, and shipment confirmations back to the brand's ERP or OMS.

1PL vs 2PL vs 3PL vs 4PL: Where Each Fits

The 'PL' tiers describe how much of the supply chain is outsourced. Understanding the distinction matters because each tier has a different EDI footprint.

• 1PL - First-party logistics. The brand owns trucks and warehouses and ships everything itself. Minimal EDI.
• 2PL - Second-party logistics. A carrier (FedEx, UPS, an ocean line) that moves freight on your behalf. EDI is mostly transportation (204, 210, 214, 990).
• 3PL - Third-party logistics. Outsourced warehousing plus fulfillment plus often transportation. Heavy EDI footprint: 940, 943, 944, 945, 947, 846, 856, 997.
• 4PL - Fourth-party logistics. A lead logistics partner that orchestrates multiple 3PLs, carriers, and brokers on your behalf. EDI is layered and often consolidated through one integration hub.

Why 3PLs Run on EDI

A 3PL is essentially a service business whose product is data accuracy. They are managing thousands of SKUs across hundreds of clients and shipping to retailers who chargeback for missed ASNs, mislabeled pallets, or late shipments. EDI is the only practical way to move that volume of orders, receipts, inventory snapshots, and shipment confirmations without humans rekeying data. A modern 3PL will typically expect you to send orders by EDI or API and receive confirmations the same way - manual portals do not scale past a few hundred orders a week.

The Core EDI Transactions Used With a 3PL

The X12 standard has a specific family of 'warehouse' transaction sets built for brand-to-3PL communication. These are the documents that flow between your ERP or OMS and the 3PL's WMS every day.

• EDI 940 - Warehouse Shipping Order. The brand tells the 3PL to ship an order to a customer or retail DC.
• EDI 943 - Warehouse Stock Transfer Shipment Advice. Notifies the 3PL that inbound inventory is on the way.
• EDI 944 - Warehouse Stock Transfer Receipt Advice. The 3PL confirms what was actually received and putaway.
• EDI 945 - Warehouse Shipping Advice. The 3PL confirms what shipped, when, on which carrier, with tracking.
• EDI 947 - Warehouse Inventory Adjustment Advice. Cycle counts, damage, write-offs, and reclassifications.
• EDI 846 - Inventory Inquiry/Advice. Periodic on-hand snapshot from the 3PL back to the brand.
• EDI 856 - Advance Ship Notice. Sent from the 3PL to the retailer (Walmart, Target, etc.) on the brand's behalf.
• EDI 997 - Functional Acknowledgment. Confirms every transaction above was received and structurally valid.

A Typical 3PL EDI Workflow, End to End

Here is what a normal day looks like between a brand, a 3PL, and a retailer when EDI is wired up correctly.

• 1. Brand drops a 940 to the 3PL for a Target DC order - SKU, quantity, ship-to, routing, must-arrive-by date.
• 2. 3PL acknowledges with a 997 within minutes confirming the 940 was accepted.
• 3. WMS picks, packs, and palletizes the order using Target's UCC-128 label requirements.
• 4. 3PL sends a 945 back to the brand confirming what shipped, on which BOL, with tracking.
• 5. 3PL sends an 856 (ASN) directly to Target before the truck arrives at the DC.
• 6. Brand sends an 810 invoice to Target referencing the same PO and ASN.
• 7. 846 inventory snapshot drops nightly so the brand's OMS knows what is sellable tomorrow.

Common Problems When Integrating a Brand With a 3PL

Most 3PL EDI integrations fail in the same handful of ways. Knowing them upfront saves weeks of go-live pain.

• SKU mismatches - the brand's item master uses different SKUs than the 3PL's WMS, so 940s reject.
• Missing or wrong retailer routing on the 940, leading the 3PL to ship the wrong carrier and trigger chargebacks.
• 945s that arrive late or never, so the brand cannot invoice the retailer on time.
• 846 inventory snapshots out of sync, causing oversells on Shopify, Amazon, or wholesale EDI 852/855 flows.
• ASNs (856) generated by the 3PL but never reconciled against the original 940 - downstream chargebacks.
• No 997 monitoring, so silent failures pile up until a retailer complains.

What to Look For in a 3PL Before You Sign

Not every 3PL is built for EDI-heavy retail. Before committing, evaluate the integration side as carefully as the warehousing side.

• Do they natively support 940/943/944/945/947 - or only API and CSV?
• Which retailers have they already onboarded (Walmart, Target, Costco, Kroger, Home Depot, Amazon Vendor)?
• Do they generate compliant 856 ASNs and UCC-128 labels per retailer routing guide?
• How fast do they send the 945 after a shipment - real time, hourly batch, or end of day?
• Do they expose a 997 dashboard so you can see acknowledgment failures?
• Can they connect via VAN, AS2, SFTP, or API - and do they charge per kilocharacter?
• Who owns mapping changes when a retailer updates their spec?

How Yoke Connects Brands to 3PLs Without the Headaches

Yoke sits in the middle of the brand, the 3PL, and the retail network. We map your ERP or OMS to any 3PL's WMS (Manhattan, Blue Yonder, HighJump/Korber, Extensiv, Da Vinci, Logiwa, ShipHero, custom) and to every downstream retailer EDI spec. That means one integration to maintain instead of one per 3PL and one per retailer.

• Pre-built maps for the major 3PLs and WMS platforms - go live in weeks, not quarters.
• Automatic 997 monitoring with alerting on missing or rejected acknowledgments.
• 940 to 945 to 856 reconciliation so you can see in one screen what was ordered, shipped, and notified.
• 846 inventory normalization across multiple 3PLs into a single on-hand view.
• Retailer compliance updates (Walmart, Target, Costco, etc.) handled for you - no mapping changes on your side.
• VAN, AS2, SFTP, and API supported on both sides of the integration.