Sending inventory to a 3PL comes down to three things: tell the warehouse exactly what is coming before it arrives, pack it so every carton can be identified without being opened, and deliver it the way the dock is set up to accept. Get those right and the shipment moves through receiving on the turnaround your warehouse quotes. Miss one and the shipment usually still gets received, but slower, possibly with extra labor charges, and sometimes with counts that take a while to untangle.
Most of that work happens before anything leaves your garage, your manufacturer or the 3PL you're leaving. The dock can only receive what the paperwork and the labels let it recognize.
What the warehouse needs before anything ships
Two things have to exist in the 3PL's system before your boxes arrive: your products and a notice of the shipment.
Your products. Each item you sell needs a record in the warehouse management system: its SKU, its barcode, a description and usually its weight and dimensions. Connecting your store may bring these records across automatically, but check that every SKU in the shipment exists and that the barcode in the system matches the barcode printed on the product. If you track lot numbers or expiration dates, the warehouse needs to know that before receiving too, because that data is captured as the goods come in.
The advance ship notice (ASN). An ASN is the warehouse's list of what to expect: which SKUs, how many of each, how many cartons or pallets, who is sending them, the carrier and tracking or PRO number, and the expected arrival date. Receiving staff check what physically shows up against it. ShipMonk's guide to its receiving process puts it plainly: every shipment a merchant sends "should have a corresponding ASN created before the freight arrives." Freight without one has nothing to be matched to, so it waits in a staging area until someone works out what it is.
The name varies by system. Some WMS platforms call it an inbound, a receiving order, a warehouse receiving order or a purchase order. ShipHero, for example, uses a purchase order. It is the same record.
You may also see the ASN described as an EDI 856. That is the electronic format big retailers and their suppliers exchange, as TrueCommerce explains. If your 3PL doesn't require EDI, you can enter the ASN in its portal or upload a spreadsheet instead; Manifest, for example, accepts both.
A few habits make the ASN useful instead of just present:
- Create one ASN per physical delivery. If a factory order ships as two containers on different dates, that is two ASNs.
- Enter quantities at the unit level, matching what is actually packed, not what you ordered. If the factory shorted you 40 units, the ASN should say so.
- Add the tracking or freight reference as soon as you have it, so the warehouse can match the delivery to the notice at check-in.
- Send it with time to spare. Many 3PLs set a minimum notice period in their terms and spell out what happens to shipments that arrive without one.
Packing cartons so the dock can receive them
Receiving goes fast when a warehouse worker can scan or read a carton and know what is inside without opening it. Every packing rule a 3PL publishes is a version of that idea.
One SKU per carton. A carton of 24 identical units can be received as a carton. A carton holding six sizes of the same shirt has to be opened, sorted and counted by hand. Some warehouses accept mixed cartons if each SKU is bagged or divided and labeled inside, as Manifest's inbound compliance policy allows, but the sorting still takes labor.
A barcode on every unit you sell. The barcode goes on the unit the customer buys. If you sell a three-pack as one item, the three-pack gets its own barcode, separate from the single units inside it. The code has to be unique and scannable. Whether it needs to be a GS1 UPC depends on where else you sell; SKU vs UPC covers that. Units that arrive without barcodes have to be labeled before they can be put away, and the warehouse may bill that work under its rate card.
A label on every carton. At minimum: your company name, the ASN or PO number, the SKU and the quantity inside. Numbering cartons ("1 of 35, 2 of 35") costs nothing and makes a missing carton obvious the moment the delivery is checked in. If your supplier already prints GS1-128 shipping labels with an SSCC barcode for retail customers, ask whether your 3PL can use them. ShipMonk notes that one scan can receive a whole carton, but only when the SSCC data is sent with the ASN through your integration; the printed label alone doesn't do it.
Soft goods in bags. Apparel, hats and other fabric items are usually expected to arrive individually poly-bagged, with the barcode on the bag. Garments that arrive loose may be bagged at the warehouse, and that labor can be billed depending on its terms.
A packing list. Put one in the shipment or email it ahead: company name, SKUs, quantity per carton and total quantity. It is what receiving falls back on when a label is damaged.
Parcel, pallet or container
How the shipment physically arrives changes what the warehouse needs from you.
Parcel | Pallets (LTL or truckload) | Ocean container | |
|---|---|---|---|
Typical source | Your garage, a small supplier, a top-up order | A domestic manufacturer, a freight forwarder, your old 3PL | An overseas factory shipping direct |
Dock appointment | Usually not needed | Required at most warehouses | Required, often with more notice |
What slows it down | Unlabeled boxes, missing ASN | Oversized or mixed pallets, no appointment | Floor-loaded cartons that must be unloaded and palletized by hand |
What to send the 3PL first | ASN with tracking numbers | ASN, carrier, PRO number, pallet count | ASN, container number, ETA, whether it is a live unload or a drop |
Parcel is the simplest. Boxes come in with the daily UPS, FedEx or USPS deliveries and need no appointment, but they still need an ASN and labels, or they sit unidentified with the rest of the day's mail.
Pallets usually travel by LTL freight for a few pallets and full truckload for a larger order; LTL vs FTL explains the difference. Use standard 40 x 48 inch pallets, keep each pallet to one SKU where you can (a single-SKU pallet can often be received as a pallet rather than carton by carton), stack cartons squarely without overhang, and stretch-wrap the load. Each warehouse sets a maximum pallet height and weight, and pallets over it may be broken down and restacked, work the 3PL can bill under its terms. Manifest, for instance, caps pallets at 63 inches tall. Ask your 3PL for its limits before the supplier builds the pallets.
Freight needs a dock appointment. Warehouses schedule trucks so they can staff the dock. ShipMonk warns that freight arriving without one "may be turned away, rescheduled, or held in a yard until a dock door opens," and a refused delivery can come back to you as a redelivery or storage charge from the carrier. Find out who books the appointment (you, your freight forwarder or the carrier) and how far ahead.
Containers add the unloading question. Cartons stacked loose on the container floor have to be unloaded and palletized by hand, which a warehouse may bill as a flat unload fee or as hourly labor, depending on its rate card. Tell the 3PL in advance whether the trucker will wait during a live unload or drop the container and come back for it later.
Briefing your factory or your old 3PL
The person packing your shipment usually isn't you. A factory or the warehouse you are leaving will pack it however it normally does unless you tell it otherwise, and you find out what it did only when the boxes reach the dock.
A manufacturer needs your requirements in writing before production finishes, not after the goods are packed. Send the barcode files for each SKU, the carton label layout you want, the rule of one SKU per carton, and your 3PL's pallet limits. Ask for a packing list with carton counts and dimensions before the shipment is picked up, and for photos of a labeled carton and a finished pallet. A photo takes the factory almost no time and can save you a relabeling bill. For goods coming from overseas, how long shipping from China takes helps you set the ASN's arrival date.
A 3PL you are leaving will pick your stock and ship it out as an order. Ask early what it will charge for that work. Request a final inventory count in writing before it ships, a packing list by carton, and the same carton and pallet rules your new 3PL uses. The count matters most: it is the number you will compare against what the new warehouse receives. How to switch 3PLs covers the cutover timing around that move.
A short version you can forward to either one:
- Ship only after the ASN is entered, and send the tracking or PRO number the day it ships.
- One SKU per carton, or each SKU bagged and labeled inside a shared carton.
- A scannable barcode on every sellable unit, including bundles and multipacks.
- Every carton labeled with company name, ASN or PO number, SKU and quantity, numbered "1 of N."
- Apparel and soft goods individually bagged.
- Standard 40 x 48 pallets, within the warehouse's height and weight limits, one SKU per pallet where possible.
- A packing list inside the shipment or emailed ahead.
- Freight booked into a dock appointment.
What happens at the dock
When a shipment arrives, the receiving team checks it in against the ASN: number of pallets, number of cartons, carton labels, and any visible damage to the outside of the boxes. Exterior damage is noted and reported to you, often with photos.
Many 3PLs don't open every carton and count every unit. ShipMonk calls its approach "good faith" receiving: it trusts that the quantity on each carton label matches what is inside. Simpl's terms of service work the same way. We compare pallet and case quantities against the paperwork and don't verify the quantities inside individual cases. Manifest's policy treats a unit-by-unit count as extra work billed under its rate card. A full count on every inbound would make receiving slow and expensive for everyone.
It does mean that your supplier's packing accuracy becomes your inventory count. If a carton labeled 24 holds 22, the warehouse system will show 24 until the shortfall turns up as an order that can't be filled or a cycle count that comes in low.
Once the counts are accepted, the stock is put away into storage and the received quantities post to your account. If your store is connected, available inventory updates there too, and the products can start selling. When a 3PL quotes a receiving turnaround, ask when the clock starts and whether it covers shipments that missed its requirements.
When the counts don't match
The warehouse will send a receiving report or update the ASN with what it actually received. Compare three numbers: what you ordered, what the supplier's packing list says shipped, and what was received.
- Fewer cartons than the ASN usually points to the carrier or to a split delivery. Numbered cartons tell you which ones are missing. Check whether the rest are still in transit before filing a claim with the carrier.
- The right cartons, the wrong units points to the supplier's packing. Ask the 3PL for photos of the carton in question, and if the problem looks wider than one box, ask it to count the SKU. Depending on the 3PL's terms, that count may be billed as labor, since it's outside standard receiving.
- Units under the wrong SKU often comes from a barcode mix-up, a product printed with another variant's code or a SKU missing from the system. Fix the barcode or the product record first so the same error doesn't repeat on the next shipment.
Take the evidence back to whoever caused the gap. A supplier that shorted a carton should credit it. For a pallet lost or damaged in transit, file a claim with the carrier; whether it pays, and how much, depends on its liability terms and the documentation you submit. The receiving report and the photos are the evidence for both.
How receiving works at Simpl
If you are sending stock to us, the core rules are the same as above. Send an inbound notice through our system (ShipHero) at least 48 hours before the shipment arrives, with an itemized list of each SKU. Pack one SKU per master carton, and put a unique barcode on each unit you sell. Receiving is free for every client, including merch drops. Shipments that don't meet our receiving requirements are billed for the extra labor at $45 per person-hour under our terms. Compliant inventory is received within 1 to 3 days of arrival at our single warehouse in Austin, TX.
Our receiving guidelines have the delivery address, pallet specifications and scheduling details. Our answer on setup and receiving fees covers what is and isn't billed. If the first inbound is part of a bigger move, the 3PL onboarding timeline shows where it fits; onboarding with us takes 5 to 7 days, and how fast you can switch to Simpl walks through a switch from another warehouse. When you are ready to talk about your own inventory, get a quote.