This is for founders and ops leads handing fulfillment to a third-party logistics provider (3PL) for the first time, or who already have and want to know what they’re paying for. We follow one order through the ecommerce order fulfillment process, from the second your customer clicks Buy Now to the carrier’s final scan at their door. By the end you’ll know every handoff, what breaks at each one, and what to ask any 3PL before you sign, us included.
We run this process for brands on our pick and pack fulfillment service from four Southern California warehouses in Jurupa Valley, Lake Forest, Commerce and Perris. Where a step works differently from one provider to the next, we say so.
The ecommerce order fulfillment process on one page
| # | Step | What happens | What goes wrong |
|---|---|---|---|
| 1 | Order ingest | Your store sends the order to the warehouse system over a direct API connection | File-based transfers lag, duplicate or drop orders |
| 2 | Address validation | The address is checked against postal data | Missing unit numbers, returned parcels |
| 3 | Allocation | Specific units are reserved against the order | Overselling when inventory counts are wrong |
| 4 | Cutoff and release | The order is released to the floor for same-day work | Orders after 2pm Pacific wait for the next processing day |
| 5 | Pick | Units are pulled from their storage locations | Wrong variant or wrong quantity |
| 6 | Pack and verify | Items are scanned against the order and boxed | An oversized box inflates billable weight |
| 7 | Weigh, rate and label | Weight and dimensions set the carrier, service and cost | A wrong weight becomes a billing adjustment later |
| 8 | Manifest and handoff | The day’s labels are closed out and parcels leave the dock | Tracking shows no movement until the first carrier scan |
| 9 | Tracking sync | The tracking number flows back to your store | Customer never receives a shipping email |
| 10 | Delivery | The carrier moves and delivers the parcel | Weather, misroutes, porch theft |
Steps 1 through 8 happen inside the warehouse. Step 9 is software. Step 10 belongs to the carrier.
Step 1: The order leaves your store
When your customer checks out, your store creates an order record: the SKUs (stock keeping units, your product codes), quantities, the shipping method they paid for, and the delivery address. On a direct API (application programming interface) connection, that record reaches our warehouse management system automatically. Nobody types it in and nobody downloads it.
The alternative is a CSV (comma-separated values) file, which is a spreadsheet export of your orders. A CSV is out of date the moment it’s downloaded, and a person has to decide which rows were already sent. That decision is where duplicate shipments and missed orders come from, and the risk grows with every sales channel you add.
We don’t accept CSV uploads. Orders come in by direct API from Shopify, WooCommerce, Amazon, TikTok Shop, eBay, Walmart, Etsy and BigCommerce, and you can see the platforms we connect to with details for each one. Whoever you talk to, ask whether the integration is a native API or a scheduled file transfer. The answer tells you how much of step 1 depends on a human.
Step 2: The address gets checked before anything is picked
Every address is checked as it enters our system, before a picker ever sees the order. Address validation compares what your customer typed against postal reference data. The USPS Address Standardization API, for example, validates and standardizes US domestic addresses to USPS addressing standards, including the ZIP+4, the four extra digits that identify a specific delivery point.
Validation catches a missing apartment or suite number, a ZIP code that doesn’t match the city, or a street number that doesn’t exist. It can’t catch a real, deliverable address that simply isn’t your customer’s. If someone types their neighbour’s valid house number, the check passes and the parcel goes to the neighbour.
An address that fails is held instead of shipped, and it needs a decision from you or your customer. This is one of the few points in the process that waits on your team. Carriers can also bill for correcting an address after a parcel is tendered [VERIFY: current UPS and FedEx address correction charge, from each carrier’s 2026 rate guide], so holding a bad address costs less than shipping it.
Step 3: Allocation reserves real units, if the count is right
Allocation means the system reserves specific on-hand units for this order, so the same last unit isn’t promised to two customers. It’s invisible when it works. When it fails, you find out at the shelf.
Allocation can only be as accurate as the inventory count behind it, and that count is set the day your stock arrives. If a carton labelled 48 units actually held 46 and was received as 48, the system will allocate two units that don’t exist. That’s why how we receive inventory does more for order accuracy than anything that happens at the pack station.
When a SKU is short, there are two choices: hold the whole order until stock arrives, or ship what’s available now and the rest later. Shipping in two parts means two picks, two boxes and two postage charges. On Shopify, each fulfillment is handled separately, so a customer can receive more than one shipping confirmation email for a split order. Set your rule during onboarding, not on the day it first happens.
Step 4: The 2pm Pacific cutoff decides which day it ships
Orders placed before 2pm Pacific get same-day processing. Orders placed after that move to the next processing day.
Here’s the part a 3PL sales page won’t dwell on: a cutoff is a line, not a guideline. An order at 2:05pm on a Tuesday ships Wednesday. 2pm Pacific is 5pm Eastern, so an East Coast customer who orders after work is already on tomorrow’s cycle. If your site promises “ships same day,” set your published cutoff at or before 2pm Pacific, and ideally a little earlier to cover address holds.
Cutoffs also matter for promotions. If you’re sending a sale email at 1pm, the orders it creates land against the cutoff all at once. Tell your account contact before the send, not after. That’s one of the practical reasons a named person beats a ticket queue.
Step 5: Pick
Picking is walking to the storage location and pulling the right units. There are three common methods. Single-order picking pulls one order at a time. Batch picking pulls several orders in one walk and sorts them afterwards. Zone picking assigns pickers to areas of the floor and passes orders between them.
The right method depends on your order profile. A brand where most orders are one unit of one SKU picks very differently from a subscription box with eight components per order. Ask any 3PL which method they’d use for your catalogue and why. A vague answer to that question is a warning sign.
Pick errors cluster around look-alikes: the 50ml and 100ml of the same serum, a medium and a large in the same colourway, two flavours in identical packaging. The fix is where those SKUs sit on the shelf and a barcode scan at the pick, not a picker trying harder.
Step 6: Pack, verify and choose the box
Every order goes through a scan-verify process before it leaves our facility. The packer scans each item, and the system compares those scans to the order. A mismatch stops the order at the bench instead of at your customer’s door. This check is what protects our 99%+ order accuracy.
Box choice is where fulfillment quietly turns into a shipping cost. Carriers charge on billable weight, which is the greater of actual weight and dimensional (DIM) weight, a figure calculated from the box’s size. UPS calculates DIM weight by dividing the box’s cubic inches by a divisor, 139 for Daily Rates and 166 for Retail Rates, and rounds any fraction up to the next whole pound. FedEx and USPS publish their own rules, so check each carrier’s current guide.
Here’s what that looks like with a 2 lb product at the UPS Daily Rate divisor:
| Box (inches) | Cubic inches | DIM weight | Billable weight |
|---|---|---|---|
| 14 x 10 x 6 | 840 | 840 ÷ 139 = 6.04, rounds to 7 lb | 7 lb |
| 10 x 8 x 4 | 320 | 320 ÷ 139 = 2.30, rounds to 3 lb | 3 lb |
Same product, same customer, more than double the billable weight. Right-sizing the carton is one of the most direct levers you have on postage.
Standard poly mailers and corrugated boxes are included in our pick and pack fee. Custom branded boxes, tissue paper, inserts, branded tape and gift messaging are add-ons. Be honest with yourself about the trade-off: a premium unboxing uses a bigger, heavier box and adds material cost to every order. Before you commit, read through the fees that show up on 3PL invoices so packaging choices don’t surprise you on the first bill.
Step 7: Weigh, rate and label
The packed carton’s weight and dimensions go into rate selection. We route each order through FedEx, UPS or USPS based on delivery speed, package dimensions and destination ZIP code, within the shipping service your customer paid for at checkout.
Printing the label is also when the tracking number is created. That’s an important distinction for your customer service team: a tracking number existing doesn’t mean the parcel has moved. It means a label exists.
The entered weight has to match the carton. Carriers set their own terms for re-measuring parcels and billing the difference, and those terms sit in each carrier’s service guide. A 3PL that weighs every carton at the bench, rather than using a saved product weight, gives you fewer adjustments to dispute later.
Step 8: Manifest and carrier handoff
Manifesting closes out the day’s labels and tells the carrier what’s coming. For USPS, a SCAN form (PS Form 5630, Shipment Confirmation Acceptance Notice) links every package in a shipment to a single barcode. When a postal employee scans that one barcode, every package on it receives an acceptance event. UPS and FedEx have their own end-of-day close-out processes.
Until that first carrier scan, your customer’s tracking page shows a label and nothing else. That gap is normal. It’s worth one sentence in your shipping confirmation email, so customers don’t read a fresh label as a stalled order.
Once parcels leave the dock, speed is the carrier’s job. From Southern California, that means 1 to 2 day ground to California, Arizona and Nevada, covering 50+ million consumers, and all 48 contiguous states through the carrier network.
Step 9: Tracking flows back to your store
Tracking numbers push back to your store automatically over the same API connection the order came in on. On Shopify, once a tracking number is attached, customers can follow the shipment through the order status page, shipping notification emails and the Shop app. When a third-party fulfillment service provides tracking, Shopify adds it automatically.
One detail to know before you switch: when an order is assigned to a third-party fulfillment service, Shopify doesn’t let you manually mark it fulfilled. The fulfillment service controls that status. If you’re used to clicking “fulfill” yourself, that habit ends on go-live day. We cover the Shopify side in more detail on our page on fulfillment for Shopify stores.
Whichever 3PL you choose, ask exactly what you’ll be able to see about an order and where you’ll see it. Get the answer in writing during onboarding.
Step 10: Delivery, and what a warehouse can’t control
After the handoff, the carrier owns the parcel. Weather, misroutes, a failed delivery scan and porch theft all happen outside the building, and no 3PL can prevent them.
What the warehouse does control is everything upstream: the right item, a validated address, a right-sized and protected carton, an accurate weight and an on-time handoff. When a parcel comes back, returns are inspected, restocked and sellable within 48 hours, which keeps a failed delivery from also becoming stuck inventory.
What 99%+ accuracy actually means at your volume
A 99% accuracy floor is not a promise of zero errors. Here’s what the floor allows at different order volumes:
| Monthly orders | Orders that could still have an error at 99% |
|---|---|
| 100 | 1 |
| 500 | 5 |
| 1,000 | 10 |
| 5,000 | 50 |
Accuracy above the floor brings those numbers down, but it doesn’t make them zero. The better question for any provider is what happens next. When a mistake is ours, we reship at no charge to you. Also ask each 3PL how they define an error, because an accuracy figure means nothing until you know what it counts.
When this process is the wrong fit for you
If you ship fewer than 50 orders a month with no growth plan, don’t outsource to us. We bill a $500/month invoice minimum, and if your charges fall short, we bill the difference. At 50 orders, that minimum alone works out to $10 an order before a single label is bought. Packing at your own table and buying labels through your store platform will cost you less, and we’d tell you so on the call.
If most of your customers are on the East Coast and your promise is next-day delivery there, a Southern California warehouse is the wrong starting point. A national provider with East Coast warehouses, such as ShipBob or ShipMonk, will get parcels to New York or Florida faster than we can by ground from California. We ship to all 48 contiguous states, but proximity is the whole point of a regional warehouse.
We also don’t handle cold-chain or hazmat products. And if the lowest possible per-order price matters more to you than a named contact and a warehouse you can drive to, we won’t be the lowest quote you get.
Questions to ask any 3PL, step by step
| Step | Ask this |
|---|---|
| Order ingest | Is it a native API connection or a file transfer, for each of my channels? |
| Address validation | What happens to an order with a bad address, and who contacts whom? |
| Allocation | How do you receive and count inventory, and what’s the split-shipment rule? |
| Cutoff | What’s the cutoff in my time zone, and does it change on weekends or holidays? |
| Pick | Which pick method fits my order profile, and how do you handle look-alike SKUs? |
| Pack | Is every order scan-verified? What packaging is included, and what’s extra? |
| Label | Is every carton weighed at the bench, or is weight pulled from a product record? |
| Tracking | How does tracking reach my store, and what can I see about each order? |
| Errors | How do you define an order error, and who pays to fix one? |
Where to go from here
If you’re shipping 100+ orders a month, your customers are mostly on the West Coast or your inventory lands in Southern California, and you want a direct contact instead of a ticket queue, talk to us. Book a 15-minute call to size your fulfillment needs. Send your monthly order volume, SKU count and sales channels, and we’ll return a quote within 24 hours. If we’re not the right fit, we’ll say so on that call.
Frequently asked questions
How long does it take a 3PL to ship an order after it is placed?
At 6G Logistic, orders placed before 2pm Pacific get same-day processing. Orders placed after the cutoff move to the next processing day. Transit time after that depends on the carrier service and the destination.
Do I have to send orders to the warehouse manually?
No. We connect to Shopify, WooCommerce, Amazon, TikTok Shop, eBay, Walmart, Etsy and BigCommerce by direct API, so orders reach the warehouse automatically. There are no CSV uploads.
What happens if a customer enters a bad shipping address?
Every address is checked as it enters our system. An address that fails validation is held instead of shipped, and it needs a corrected address from you or your customer before it can go out.
Can 6G Logistic fulfill cold-chain or hazmat products?
No. We don’t handle cold-chain or hazmat fulfillment. Brands that need either should work with a provider that specializes in it.