To choose a 3PL provider, start by defining what your business needs now and in the next two to three years, then shortlist providers that fit your budget, order volume, channels and customer locations. Interview your finalists with the same set of questions. Then verify what you can before you sign. Ask how the provider measures performance and how it held up last peak season, talk to current clients, see its systems in action and read the contract for how performance is measured and what happens when it slips.
Where something can’t be proven upfront, a phased start lets you confirm performance with your own orders before moving all of your volume. Most order fulfillment services look the same in a sales deck. The difference shows up in the details, and this guide walks through what to look for at each step.
Deciding on Your 3PL Search Criteria
Outsourcing fulfillment makes sense once handling it yourself starts costing more than it should, in space, staff or missed delivery promises, and gets harder to scale with each peak season. Before you look at a single provider, write down what you need. In the short term, that usually means order volume, the channels you sell through, any special handling your products require and the delivery speed your customers expect. In the long term, it means where you plan to grow, such as new channels, wholesale and retail accounts, or new regions.
These criteria become your filter. A provider that’s a strong fit for a single-channel DTC brand may struggle with retail compliance requirements, and a provider built for large B2B shipments may not suit a brand shipping thousands of small parcels a day. Defining the criteria first keeps the search focused on what matters to your business, not on whoever has the best pitch.
Identifying Your Best Options
Start with referrals from peers in your industry, then research providers’ websites, case studies and customer reviews. Narrow the list by budget, pricing transparency, ability to handle your current and projected order volume, and fulfillment center locations relative to your customers, since closer inventory means lower shipping costs and faster transit times.
Scope matters at this stage, but it rarely separates good providers from weak ones. Most order fulfillment services cover the same core work: receiving and storing inventory, picking and packing orders, shipping them and processing returns. Many providers add kitting, FBA prep, custom packaging and B2B or retail fulfillment. For a breakdown of what’s typically included and how pricing works, see our guide to 3PL services and costs. If you’re still deciding whether to outsource at all, start with outsourced versus self-fulfillment.
Interviewing Your 3PL Options and What Questions to Ask
Interview every finalist with the same questions so you can compare answers side by side. Every 3PL will say it’s accurate, fast and scalable. Follow each question with a request for specifics, so you can tell a considered answer from a sales line.
| Category | What to ask | What a strong answer includes |
|---|---|---|
| Technology and integration | Which warehouse management system do you run? Does it integrate with our ecommerce platform, marketplaces and ERP? How is inventory tracked and secured? | A walkthrough of the client portal and standard reports, how often data refreshes and how integrations are set up and tested during onboarding |
| Fulfillment and shipping performance | What are your order cutoffs and processing times? Which carriers do you use and how are rates set? How are returns handled? | Recent on-time shipment, order accuracy and inventory accuracy figures, with a clear definition of each |
| Scalability and peak | How do you handle seasonal spikes? Can you support new channels or regions? Which industries do you specialize in? | How last year’s peak was planned and staffed, when capacity is locked and how performance held up |
| Customer service and support | Will we have a dedicated account manager? How are disruptions communicated? How are disputes over lost or damaged inventory resolved? | References from current clients of similar size and category, and a documented escalation path |
The answers tell you how a provider thinks. The next step is checking them against everything else you can learn about how it operates.
Verifying a 3PL Before You Sign
The gap between a good interview and a good partner is verification. This is the stage most brands rush. Providers differ in how much they can share before a contract is in place, so focus on what tells you the most and plan to confirm the rest during a phased start.
Ask how performance is measured
Ask each finalist which metrics it tracks, what its recent results look like and how they held up during peak season, not just a single annual average. Compare what you hear with industry benchmarks. In WERC’s 2025 DC Measures report, as summarized by Yale, best-in-class operations ship 99.5% or more of orders on time, pick orders with 99.68% or better accuracy, and move inbound inventory from dock to stock in under 3.5 hours. A provider doesn’t have to hit every best-in-class mark to be a good partner. It should know its own numbers, define them clearly and be able to talk through where it has fallen short and what changed.
Definitions matter as much as the numbers. Ask whether order accuracy is measured by order or by line, whether on-time means shipped by cutoff or delivered by promise date, and whether the figures cover all clients or a single site. A 3PL that can’t answer these questions quickly probably isn’t managing to them.
What order accuracy rate should a 3PL deliver?
A strong 3PL should deliver order accuracy above 99.5%, and best-in-class warehouses pick at 99.68% or better, according to WERC’s 2025 DC Measures benchmarks. Ask how accuracy is measured, by order or by line, and how it held up during peak season. A provider that can’t explain how it measures accuracy probably isn’t managing to it closely.
See the technology in action
Integration problems are expensive to discover after go-live. Ask for a live walkthrough of the client portal and reporting, and ask how integrations with your ecommerce platform, marketplaces and ERP are built and tested during onboarding. Walk through how your most complicated orders, such as bundles, subscriptions, B2B orders and marketplace orders, would be handled. Once you’re live, inventory should update across your sales channels in near real time, order status and tracking should flow back without manual uploads, and you should be able to see receiving, inventory and shipment detail yourself instead of requesting it through an account manager.
Ask for proof of peak performance
Most fulfillment failures happen in November and December, when volume can multiply in a few weeks. Ask each finalist how it planned for its busiest weeks last year, how far in advance it locks staffing and capacity, and what happens if you beat your forecast. A provider with a real peak plan can describe it in specifics: the dates it adds shifts, how it prioritizes clients when volume spikes and which cutoffs move. Vague answers about scaling with demand are a reason to keep asking.
Making Your Selection
The contract is where a 3PL’s confidence in its own operation shows up. Look for service level agreements that name specific metrics, the same ones you discussed in interviews, along with how they’re measured. Ask what happens when a target is missed. Remedies vary by provider, from service credits to corrective action plans, but the process should be in writing.
Then review the fee schedule line by line. Ask for every charge in writing, including receiving, storage, packaging and handling, special projects, returns, minimums and peak-season surcharges, and model them against your actual order profile. Finally, check the terms that matter if things go wrong: contract length, termination rights, who owns your data, how inventory loss and damage are handled, and how long it takes to get your inventory out.
What should be in a 3PL contract?
A 3PL contract should define service levels for on-time shipping, order accuracy and inventory accuracy, explain how each is measured, and set out what happens when the provider misses them. It should list every fee, including accessorial and peak-season charges, and set out minimums, contract length, termination rights, data ownership and liability for lost or damaged inventory. If a term isn’t in writing, assume it doesn’t apply.
Use a scorecard to compare finalists
Example 3PL evaluation scorecard
A weighted scorecard turns the evidence you’ve gathered into a decision you can defend internally. Score each finalist from 1 to 5 in each category, multiply by the weight and compare the totals. The weighting above is an example for a DTC brand shipping 3,000 to 20,000 orders a month, with operational performance weighted highest because it drives customer experience most directly. A brand with heavy wholesale volume might weight B2B capability higher, and a brand with temperature-sensitive products might add a category for compliance. The value comes from setting the weights before you see the proposals, so the most polished pitch doesn’t win by default.
Start with a pilot
The best evidence is your own orders flowing through the provider’s operation. Instead of moving all of your volume at once, start with a portion of your catalog, a single channel or a single region, and expand once the provider hits the targets you agreed on. A phased start limits risk and gives both teams time to fix problems before peak.
UV Skinz, a sun-protective apparel brand, took this approach when it moved fulfillment to Cart.com. Onboarding started with 30% of the brand’s operations and scaled to 100% once performance was proven. Today the brand runs at a 100% order fill rate.
Working With Cart.com
Cart.com runs 15 fulfillment and distribution centers, fulfills more than 85 million orders a year and supports DTC, B2B, marketplace and retail channels from one network. Its order and warehouse management systems give brands direct access to inventory, order and returns data, and a dedicated onboarding team runs phased rollouts like the UV Skinz transition above.
The results hold up after signature. Thursday Boots processes 100% of its returns within 24 hours with Cart.com and returns 96% of returned inventory to stock, measured results rather than projections.
Frequently Asked Questions
How do I choose the right 3PL provider?
Define your short- and long-term fulfillment needs, shortlist providers that fit your budget, volume, channels and customer locations, and interview finalists with the same questions. Then verify what you can with performance metrics and how they’re defined, client references, a system walkthrough and a close contract review, and start with a pilot before moving all of your volume.
What KPIs should I ask a 3PL for?
The most important KPIs are on-time shipment rate, order accuracy, dock-to-stock time and inventory accuracy. Ask for recent figures, how each one is defined and measured, and how performance held up during peak season.
What are order fulfillment services?
Order fulfillment services are the steps a 3PL handles to get an order from inventory to the customer: receiving inbound stock, storing it, picking and packing each order, shipping it and processing returns. Many providers also offer kitting, FBA prep, custom packaging and B2B or retail fulfillment.
How long does it take to switch 3PLs?
Most 3PL transitions take several weeks to a few months, depending on catalog size, integrations and how much inventory needs to move. A phased onboarding that starts with part of your volume reduces risk and lets you confirm performance before peak season.
How is Cart.com pricing determined?
Cart.com pricing depends on the services a brand uses and the complexity of its operation. Fulfillment, marketplace, marketing and technology services are scoped separately, so brands pay for the mix they need.
See the Evidence for Yourself
The right fulfillment partner should welcome your questions and answer them clearly. If you’re evaluating providers, contact Cart.com’s fulfillment team to talk through your order profile, your integrations and a phased onboarding plan, or learn more about Cart.com fulfillment.
Related reading: 3PL Services: What’s Included, What It Costs, and How to Choose, Outsourced Versus Self-Fulfillment, Ecommerce Order Fulfillment Company: Comparing Top Providers
