EDI for 3PL fulfillment: the basics for warehouse owners

EDI is the exchange of business documents between companies in an agreed machine readable format, which in North America is usually X12. Sooner or later a client with a retail customer signs a contract that says "must support EDI", and then they turn to you. If you have only worked with storefront orders, EDI can look like a foreign language. It is mostly a small set of structured messages, and a lot of waiting for a trading partner to approve your tests.

This guide explains the plain version: what the messages are, who sends them, and what to settle before you say yes.

What EDI is

EDI stands for electronic data interchange. It means two companies exchange business documents, such as orders and shipping notices, in an agreed machine-readable format instead of by email or spreadsheet. The retailer sets the rules. You follow them.

In North America the common standard is called X12. Each document type has a number. Your retailer will usually supply a guide that says exactly which fields they expect.

The messages a fulfillment 3PL usually sees

Different setups use different documents. This is a typical flow for a client selling through a big retailer, where your warehouse ships on the client's behalf:

• Purchase order (850). The retailer sends an order to the client. Depending on the arrangement, it reaches you directly or through the client.
• Warehouse shipping order (940). The client, or their system, asks you to ship it. This is the instruction to your warehouse.
• Warehouse shipping advice (945). You tell the client what actually shipped, with quantities and tracking.
• Ship notice/manifest (856), often called the advance ship notice or ASN. A notice to the retailer saying what is in the shipment and how it is packed, often cartons and pallets with labels.
• Invoice (810). The bill for the goods, usually sent by the client, not you.
• Inventory inquiry/advice (846). A periodic report of stock levels.
• Functional acknowledgment (997). A receipt that says a message arrived and was readable.

Check these against what your own partners require. Some retailers ask for fewer, some for more. Some of the above may be handled by the client's own system rather than yours.

Where the 3PL fits

There are three common arrangements:

1. The client handles EDI. They exchange messages with the retailer and send you simple instructions. Your job is to ship correctly and report back.
2. You handle EDI on the client's behalf. You receive the retailer's documents, ship, and send the advance ship notice. This is a service you can charge for.
3. A third-party EDI provider sits in the middle. They translate between the retailer and you. Each message passes through them.

Know which arrangement you are in before you quote. Much of the pain in EDI projects comes from two parties each assuming the other owns the messages.

Why the label matters as much as the message

The advance ship notice describes what is in each carton and pallet, and those cartons carry a barcode label. If the label does not match the notice, the retailer's dock may reject the delivery.

So EDI is not only software. Your packing process has to produce the label, in the format the retailer asks for, and your system has to send a notice that matches it. Test with a real shipment before the first live order.

Questions to settle before you say yes

1. Which documents does this retailer require, and in which version?
2. Who is responsible for each document: you, the client, or a provider?
3. How do you connect? Directly with the retailer, or through a network or provider? Who pays for it?
4. What does testing involve? Retailers may require a test phase before approving a new sender. Ask how long it takes, and who has to be available.
5. What are the penalties? Some retailers may set charges for late or inaccurate notices. Read the routing and compliance guide for the exact terms.
6. What if a message fails? Who gets alerted, and who fixes it?
7. What is the labeling requirement? Size, content, placement.

Write the answers down. If the client cannot answer them, that tells you the project is not ready.

What your system needs

Whether you build or buy, check that your warehouse system can do the following:

• Receive an order or shipping instruction and turn it into a pick.
• Record cartons and pallets as they are packed, with the identifiers that go on the labels.
• Produce the shipping label in the retailer's format.
• Generate the outgoing notice from what was actually packed, not from what was ordered.
• Keep a log of every message sent and received, with timestamps.
• Show errors in a place someone will see them.

The "from what was packed" point is the one that bites. If the notice is built from the order and the packers made a change, the notice is wrong.

Pricing EDI as a service

Pricing this is your decision. Think through the work involved: setup, testing, ongoing monitoring, and handling failed messages. Decide whether you charge a setup fee, a monthly fee per client, or a fee per document, and say it in the contract. Do not copy numbers from somewhere else; start from your own time and costs.

A small example

Hypothetical example: a client sells a toy line to a national retailer. The retailer's guide says it wants an advance ship notice sent no later than the moment the truck leaves, with pallet-level labels.

You decide to handle EDI for this client. The work includes: setting up the connection, mapping fields from your system to the notice, testing with the retailer, creating the label template, and training packers. After approval, you monitor each shipment. You charge setup plus a monthly fee. The client's chargeback risk goes down because you own the process end to end.

Another 3PL in the same situation might leave EDI with the client and charge only for shipping. Both are fair.

Next step

Ask your client for the retailer's compliance guide. Read it with your operations lead, and mark every requirement that touches your floor. That list, not the software, is what you actually take on.

Questions people ask

What is EDI for a 3PL?

EDI stands for electronic data interchange. Two companies exchange documents such as orders and shipping notices in an agreed format instead of by email or spreadsheet, and the retailer sets the rules.

Which EDI messages does a fulfillment 3PL usually handle?

Typical ones are the 850 purchase order, 940 warehouse shipping order, 945 warehouse shipping advice, 856 ship notice, 810 invoice, 846 inventory advice and 997 acknowledgment. Check them against what your own retailers require.

Who is responsible for EDI, the 3PL or the client?

It varies. The client may handle it, you may handle it on the client's behalf, or a third party provider may sit in the middle. Settle which arrangement applies before you quote.

Why does the label matter in EDI?

The advance ship notice describes what is in each carton and pallet, and the barcode label has to match it. If it does not, the retailer's dock may reject the delivery.

What should I ask before agreeing to provide EDI?

Ask which documents and versions are required, who owns each one, how you connect, and what testing involves. Also ask what penalties apply, what happens when a message fails, and what the labeling requirement is.

What do the EDI 850, 940, 945 and 856 messages mean?

The 850 is a purchase order, the 940 a warehouse shipping order, the 945 a warehouse shipping advice and the 856 a ship notice. Always confirm which sets and versions each retailer's own EDI guide requires.