3PL Onboarding Checklist

Phase	What happens	Your deliverables
1. Kickoff and data	Account set-up, contacts, SOPs	SKU master, packing rules, returns rules
2. Integrations	Store and marketplace connections, SKU and ship-method mapping	App installs, credentials handled through the app's own authorization
3. First inbound	You ship stock; the 3PL receives and counts	ASN, labeled cartons, expected counts
4. Testing	Test orders through each channel and rule	Test plan and sign-off
5. Go-live and hypercare	Live orders; daily check-ins	Exception triage, first invoice review

Providers set their own timelines and fees: Simpl Fulfillment cites 5–7 day onboarding with no setup fee; Thrive 3PL says most brands pay $200–$500 for onboarding; Fulfyld gives the first two hours of receiving free at onboarding, then $40 an hour. Ask for a written onboarding plan with dates and owners.

• SKU master: SKU, name, barcode (UPC/EAN or 3PL label), unit weight, unit dimensions, case pack, and case dimensions
• Variant barcodes: every size, shade and flavor gets its own barcode; look-alike variants cause mispicks
• Lot and expiry flags for anything dated. See lot tracking and FEFO
• Hazmat flags (perfume, aerosols, batteries)
• Kits and bundles: bill of materials for each
• Packing rules: box selection, fill, branded materials, inserts, gift notes, with photos
• Ship-method mapping: each checkout option to a carrier service
• Returns rules: restock, B-stock or dispose, by condition
• Contacts and escalation path on both sides
• Holiday and peak calendar with forecasts

Most 3PLs connect through a Shopify app. Shopify describes app-based fulfillment services as location-based: you stock items at the fulfillment service's location, and the app syncs inventory with your admin.

Setup steps:

1. Install the 3PL's app and authorize it.
2. Assign inventory to the 3PL's location for every product it will ship.
3. Decide on automatic fulfillment. With it on, Shopify requests fulfillment automatically when the order is paid. With it off, you request it manually.
4. Map ship methods from checkout rates to the 3PL's carrier services.
5. Confirm tracking sync. The app updates tracking when the service ships.
6. Agree a cancellation process. Shopify notes that reverting an order to unfulfilled doesn't stop the fulfillment service from fulfilling it, and requests the service has already accepted need its approval to cancel. Agree a cut-off time and channel (ticket, email, portal) for cancellations and edits.

For Amazon, TikTok Shop, Walmart and wholesale, repeat the mapping per channel. See multichannel inventory with a 3PL.

1. Create an ASN in the 3PL's portal: SKU, quantity, lot/expiry, number of cartons or pallets, carrier and ETA.
2. Label every carton with SKU and quantity, one SKU per carton where you can.
3. Send a packing list inside the first carton and a copy by email.
4. Book a dock appointment if you're shipping freight.
5. Get the receiving report and compare expected vs. counted, SKU by SKU.
6. Resolve variances before go-live: miscounts, damage, unlabeled cartons.

If you're moving stock from another 3PL, follow switching 3PL providers, because the old 3PL's pick-out has its own risks.

Run real orders through every path you'll use:

Test	Pass when
Single-item order per channel	Syncs, ships, tracking writes back
Multi-item order	Right box, all items, scanned
Each ship method	Correct carrier service selected
Kit or bundle	Components deducted correctly
Insert rule (GWP, first order)	Insert is included only when the rule applies
Lot-controlled SKU	Earliest-expiry lot ships
Cancellation before cutoff	Order doesn't ship
Address edit	Label uses new address
Return	Received, graded, inventory updated

Photograph each packed test order before sealing and compare it with your packing rules.

• Daily: orders released vs. shipped, orders on hold, exceptions queue.
• Weekly: on-time ship rate against the cutoff, mispick reports, customer tickets tagged "shipping".
• At day 30: first full invoice line by line, a cycle count on your top SKUs, and a review call against the SLA.

Common onboarding failures: products assigned to the wrong Shopify location, so orders never reach the 3PL; ship methods unmapped, so everything goes by the slowest service; stock received but not released to sellable; the old fulfillment method still active, so orders get shipped twice.