How To Know When You Need To Outsource Fulfillment
When to outsource fulfillment: 7 signs, from order volume and cost per order to errors, space and time, plus the numbers to check before you call a 3PL.
Choosing a 3PLOctober 18, 202211 min read
3PL onboarding is the stretch between signing with a third-party logistics provider (3PL) and shipping orders from its warehouse without surprises. For a first-time brand it runs in six stages: kickoff, product data and integrations, the first inbound shipment, test orders, go-live and a 90-day review. Your part is to hand the 3PL clean SKU data, accurate advance shipping notices (ASNs), working store connections and written packing rules before any stock arrives. Get those four right and most first-month problems never happen.
This guide starts after you have picked a provider. If you are still comparing warehouses, start with how to choose a 3PL provider. If you are moving from one 3PL to another, the guide to switching 3PL providers covers exit terms and running two warehouses in parallel.
What Is 3PL Onboarding?
Onboarding is the project that turns a signed contract into a working operation. The 3PL sets up your account in its warehouse management system, connects it to wherever you sell, receives and counts your inventory, and learns how you want orders packed. You supply the information each of those steps depends on. Many 3PLs assign an onboarding lead, who hands you to an account manager once orders flow.
The onboarding process with a 3PL usually runs in this order:
- Kickoff. Meet the people who will run your account, agree on contacts and escalation paths, and put the service level agreement (SLA) in writing.
- Data and integrations. Send your SKU file and connect your store, marketplaces and any wholesale systems.
- First inbound. Book the delivery, send an ASN and have the 3PL receive and count your stock.
- Test orders. Push test orders from every sales channel through picking, packing and labeling.
- Go live. Real orders flow, with daily check-ins for the first weeks.
- 90-day review. Measure the 3PL against the SLA and fix what the first months exposed.
How Long Does 3PL Onboarding Take?
For a straightforward ecommerce account, plan on weeks rather than months. DCL Logistics, a 3PL, writes that integration should take "a few weeks at most," and treats onboarding that drags past four to six weeks without a clear go-live date as a warning sign. Ryder recommends finishing end-to-end testing at least one week before go-live and holding a formal 90-day evaluation afterward. Custom integrations, kitting, lot tracking and a long SKU list all add time, so ask for a dated project plan at kickoff.
What to Prepare Before Your 3PL Receives Anything
A 3PL can only be as accurate as the information you give it. Have these ready, roughly in the order the 3PL needs them.
1. A Complete SKU File
Send one spreadsheet with a row for every SKU you will store, including bundles and inserts. Many 3PLs have a template; fill in every column. At a minimum it should cover:
| Field | Why the 3PL needs it |
|---|---|
| SKU and product name | Matches the item names your store sends with each order |
| Barcode (UPC or other GTIN) | Scanned at receiving, picking and packing to catch errors |
| Unit weight and dimensions | Drive box choice and shipping cost, which carriers price partly on dimensional weight |
| Case pack | Units per carton and cartons per pallet, so the dock can count cartons instead of single units |
| HS code and country of origin | Needed for international orders and customs clearance |
| Handling flags | Fragile, hazardous, temperature-sensitive, or tracked by lot or expiry date |
Weights and dimensions sent up front also give you more accurate shipping estimates before inventory lands. Take care with HS codes if you ship abroad: a wrong code can hold orders up at customs. And tell the 3PL about anything fragile, hazardous or temperature-sensitive before it arrives, for the safety of the stock and the people handling it.
If your products do not carry barcodes yet, sort that out now. GS1 US, which issues UPC barcodes, describes a GTIN as a globally unique number that identifies your specific product, and each variation of each product you sell needs its own barcode. Some 3PLs can label unbarcoded units for a fee.
2. ASNs and a Receiving Plan
A busy warehouse takes in many deliveries a day, and the dock team cannot tell what is inside a carton by looking at it. That is why every 3PL asks for an advance shipping notice (ASN), sometimes called a warehouse receiving order (WRO), before a delivery arrives. It usually asks for:
- each SKU and the quantity shipped;
- how it is packed: cartons, pallets and units per carton;
- the carrier, its contact details and the tracking or reference number;
- your purchase order number and the expected arrival date.
Accuracy matters more than speed. Leaving a SKU off the ASN creates extra work for the 3PL and delays your orders. Small factory overruns are normal: if the ASN says 1,000 units and 988 or 1,035 arrive, that is rarely a problem. If 600 or 1,400 arrive, the 3PL has to stop and recount before anything is put away, which costs time and usually money.
Send the 3PL's inbound requirements (carton labels, pallet rules, one SKU per carton or mixed) to your suppliers and freight forwarder before they ship, and point future purchase orders at the new address. Ryder calls suppliers a critical link in the transition for this reason.
3. Integrations and Order Flow
Orders need to reach the 3PL automatically, and stock levels and tracking numbers need to flow back. Before kickoff, list every place you sell and every system that touches an order: your store platform, each marketplace, wholesale accounts that order through EDI, and any ERP or inventory tool. Then confirm with the 3PL:
- which connections are prebuilt and which need an API build or middleware;
- which system is the source of truth for inventory counts;
- how the shipping options in your store map to the carrier services the 3PL uses;
- what the integration costs (Ryder notes some 3PLs charge a one-time fee and others a smaller recurring monthly fee);
- who troubleshoots when an order fails to sync.
In the 2026 Annual Third-Party Logistics Study, 90% of shippers regarded technology capabilities among the most critical elements in selecting a 3PL. It is also where first-month problems hide.
4. Packing, Shipping and Returns Rules
Left to its own judgment, a 3PL will usually pack and ship the cheapest way that works: a poly mailer instead of a box, the lowest-cost carrier service. That is often the right call, but it is your brand arriving on the doorstep. If you sell board games, for example, ask for a rigid box, or the game can arrive with dinged corners.
Write your rules down, per SKU where it matters:
- Packaging: approved boxes and mailers, void fill and any branded materials.
- Inserts: samples, gift notes and marketing pieces, and when to include them.
- Kits and bundles: step-by-step kitting instructions with photos.
- Carriers: which carriers and services to use, and when to upgrade.
- Returns: how to inspect, grade and restock returned items, and when to dispose of them.
Settle returns before launch, not after. Retailers estimated that 19.3% of online sales would be returned in 2025, according to the National Retail Federation and Happy Returns, so returns will reach your 3PL soon after launch. A written RMA process keeps them from piling up.
5. A Forecast and a Named Owner
A 3PL plans space and labor from what you tell it. Share a 12-month order forecast, planned promotions, product launches and seasonal peaks at kickoff, and update it as plans change. On your side, name one person who owns onboarding and answers the 3PL's questions quickly.
Ask the 3PL for the same: an onboarding lead now and a dedicated account manager after go-live. Tell your account manager your goals and concerns early; good 3PLs will ask, but a little self-advocacy goes a long way. For the questions worth asking at this stage, see questions to ask a new 3PL.
Test Before You Go Live
Integration checks prove data moves; a test run proves orders ship correctly. Ryder recommends finishing comprehensive testing at least one week before your go-live date. Place test orders from every channel and follow each one through:
- the order arriving in the 3PL's system with the right SKUs, address and shipping method;
- picking, packing to your packaging rules, and labeling;
- tracking flowing back to your store or marketplace;
- inventory counts updating on both sides;
- edge cases: a bundle, a multi-item order, an international order and a return.
Fix what breaks, then test again. DCL lists delayed or deprioritized testing among the red flags in a new 3PL, because problems it misses surface once real orders go live.
Your First 30, 60 and 90 Days With a 3PL
Days 1 to 30: Stabilize
Hold short daily check-ins for the first weeks. Watch for orders stuck between systems, deliveries received short or over the ASN, and packing mistakes. Audit the first invoice line by line against your quote: receiving, storage, pick and pack, packaging and shipping should each match the rates you signed. The 3PL pricing guide explains the usual fee lines.
Days 31 to 60: Measure
Move to a weekly meeting with a short scorecard: on-time shipments, order accuracy, receiving time, inventory accuracy and open tickets. Ask for the 3PL's first cycle counts and compare them with your own records.
Days 61 to 90: Review
Hold a formal 90-day review. Compare each metric with the SLA, agree on fixes with an owner and a date for each, and update the SLA where the first months showed it was wrong. Ryder describes this review as a chance for both sides to debrief on onboarding and carry the lessons into continuous improvement.
What Good Looks Like After 90 Days
Your SLA sets the targets that count, but it helps to know what strong warehouses achieve. The Warehousing Education and Research Council (WERC) surveys distribution and fulfillment operations every year. Its 2025 DC Measures report puts the top 20% of respondents at these levels:
| Metric | What it measures | Top 20% of warehouses |
|---|---|---|
| On-time shipments | Orders shipped at the planned time | 99.5% or more |
| Order picking accuracy | Orders picked correctly | 99.68% or more |
| Dock-to-stock cycle time | Time from a delivery's arrival to stock recorded in inventory | Under 3.5 hours |
These are warehouse benchmarks, not terms most 3PLs will put in a contract, and your SLA may measure receiving in days rather than hours, so ask how each metric is defined. Small percentages matter: at 99.68% picking accuracy, about 32 of every 10,000 orders are still picked wrong, and any the pack station misses reach customers that way.
Red Flags During Onboarding
- No written SLA, receiving standards, returns process or escalation path.
- No dated project plan or shared place to track open tasks.
- Testing skipped or squeezed into go-live week.
- Nobody named to run your account once orders start.
- A first invoice that does not match the quoted rates.
Most of these come from DCL's list of onboarding red flags. Several still open at the 90-day review are a reason to escalate.
3PL Onboarding FAQ
What does a 3PL need from me to get started?
A SKU file with barcodes, weights, dimensions, case packs, HS codes and handling flags; an ASN for every inbound shipment; access to your store and marketplaces; written packing, shipping and returns rules; and an order forecast.
Who pays for 3PL onboarding?
It depends on the contract. Setup and integration can be a one-time fee or a recurring monthly charge, and labeling inventory that arrives without barcodes can be billed as extra work. Get every onboarding charge in writing before you sign.
Can I start with only some of my SKUs?
Yes. Ryder suggests an ABC approach when moving stock: send your fastest-selling "A" items first so they are ready to pick at go-live, and consider whether slow or non-moving items are worth moving at all.
Find a 3PL That Fits Before You Onboard
Onboarding goes smoothest with a 3PL that already handles products, volumes and sales channels like yours. Fulfill.com matches brands with 3PLs based on what they ship, how much and where their customers are. Tell us about your business and get matched with 3PLs.
