Costco's EDI program is shaped by its depot network: orders arrive per depot, freight books against depot appointments, and the two setup tasks that repay the most care are both cross-reference tables. Plan 2–3 days for the technical build. Here's the sequence for Costco, start to finish — with the underlying requirements covered in the Costco EDI requirements guide.
1. Settle the vendor prerequisites
You need an active Costco vendor relationship, your vendor identifiers, and items set up on Costco's side before documents flow. One data question to resolve immediately: pack and size definitions. Costco's definitions differ from what most suppliers keep in their master data, and the mapping must be explicit — a "case" that means twelve units to you and something else to Costco will corrupt quantities on every document until someone notices at a depot dock.
2. Establish connectivity — the VAN question
Unlike the AS2-direct crowd, Costco still trades through VAN interconnect for many suppliers. Historically that meant a separate VAN contract and a kilocharacter bill; with EDISQ the VAN hop is simply part of the route, included in the per-document price. Practically, this step is zero work on your side — the platform routes to Costco however Costco wants to be reached — but it's worth knowing the topology when you're debugging a delayed 997.
3. Attach your ERP and build the depot table
Connect the business system — NetSuite, Acumatica, or any of the 30+ supported platforms — so Costco orders materialize as sales orders without re-keying. Then build the two tables this partner lives on. The depot cross-reference maps Costco's ship-to depots to your location logic; facts on the ground say this is the most common failure point on inbound 850s. The pack table encodes those explicit Costco pack/size definitions from step one against your SKUs.
4. Test the depot round trip
Sandbox testing should walk a complete depot cycle. Take in an 850 addressed to a depot and confirm the ship-to resolves and quantities land in the units your warehouse picks. Generate the 856 and check the two rules Costco receiving enforces: the ASN posts before the depot appointment, and GS1-128 carton labels carry serials matching the MAN segments in the document. If labels and ASN both derive from one pack-out record, that second rule passes structurally; if they don't, fix the plumbing now rather than after the first deduction under Costco's depot compliance program.
5. Certify and switch on the monitors
Certification is a short loop with pre-built maps. At go-live, enable acknowledgment tracking and appointment-aware ASN timing — the 856 should fire when the warehouse ship-confirms, giving it comfortable margin over any appointment. From there, day-two operations are mostly watching dashboards stay green.
Who you need in the build
Depot programs go smoothest when three roles contribute before certification. Someone from operations owns the pack question — they know what a Costco case, inner, and unit really are for each SKU, and that knowledge has to land in the pack table rather than stay in their head. Someone from the warehouse confirms how carton labels are produced today, since the GS1-128-to-MAN match depends on that process feeding the ASN. And someone from finance reviews the first sandbox invoice against a real-world example. None of these is a large time commitment; all three prevent the kind of rework that turns a three-day setup into a three-week one.
The bill
Costco traffic prices like all EDISQ traffic: your first 25 documents each month are free, then the meter starts at $0.50 per document and glides to $0.10 at the highest volume band, with marginal-tier billing so earlier documents never get re-priced. The VAN interconnect, the certified Costco maps, and the sandbox are already in that rate — no mapping or setup line items, and a $100/month Production minimum that applies in full to usage with Costco included as your first live partner. Numbers and a calculator at pricing.
FAQ
Does Costco EDI require a VAN?
Costco still trades through VAN interconnect for many suppliers. With EDISQ the VAN hop is folded into the per-document price — no separate VAN contract or bill.
How many days does Costco EDI setup take?
Around 2–3 days on the EDI side with certified maps. Depot cross-references and pack mapping are the tasks that deserve the most care.
What trips up new Costco suppliers most?
The depot ship-to cross-reference on inbound orders, and pack/size definitions — Costco's differ from typical master data and must be mapped explicitly.
When does Costco expect the ASN?
Before the depot appointment, with GS1-128 carton labels matching the MAN segments in the 856.