If your business uses a third-party logistics provider — whether for warehousing, fulfilment, freight brokerage, or last-mile delivery — you are almost certainly already in an EDI relationship, whether you realise it or not. The question is whether your side of that relationship is automated and accurate, or held together with email and spreadsheets.
What 3PLs Actually Need From Their Clients
A 3PL managing your inventory needs real-time data to do its job. That means knowing:
- What purchase orders are coming in and when
- Which orders to pick, pack, and ship — and to which address
- What labels to print, including SSCC barcodes for retail compliance
- When to generate an 856 on your behalf to the end buyer
- What inventory levels look like across their facilities
Most established 3PLs exchange this information via EDI. The standard transaction sets in a shipper-3PL relationship include the 940 (Warehouse Shipping Order), 945 (Warehouse Shipping Advice), 944 (Warehouse Stock Transfer Receipt), and 943 (Warehouse Stock Transfer Advice) — in addition to the retailer-facing 850, 856, and 810 flows.
The Data Sync Problem
When a 3PL and a supplier are not connected by EDI, they typically resort to portal data entry, email attachments, or CSV uploads. The problems are predictable:
- Orders take hours to reach the 3PL after the buyer sends them
- Ship confirmations are delayed, causing late 856 transmissions and retailer chargebacks
- Inventory counts drift out of sync between the 3PL's WMS and the supplier's ERP
- Returns and adjustments require manual reconciliation
Each of these delays and errors has a cost — in chargebacks, in staff time, and in the quality of service you can offer your end buyers.
What a Connected 3PL Relationship Looks Like
When EDI is running cleanly between a supplier and their 3PL, the flow is largely invisible. An 850 arrives from a retailer. Your EDI platform sends a 940 to the 3PL automatically. The 3PL picks, packs, and ships — then sends back a 945 confirming what went out. Your platform converts that 945 into an 856 for the retailer and an 810 invoice. No one in your business has to touch the transaction.
Choosing a 3PL With EDI in Mind
If you are evaluating 3PLs, ask specifically which EDI transaction sets they support, which transport protocols they use (AS2 is preferred for retail compliance), and whether they can provide SSCC label generation for retailer shipments. A 3PL that cannot generate 856-compliant SSCC labels is going to create compliance headaches with your retail trading partners — regardless of how good their warehousing operations are.
The logistics layer of your business only runs smoothly when the data layer matches it. EDI is how you make that happen.