Prioritize reliable highway access and carrier density for predictable transit times, WMS functionality for inventory visibility, cross-dock and sortation capacity for fast throughput, temperature control if required, and proven integrations (API/EDI) with your store and carrier partners to automate tracking and billing.

Location influences transit miles, fuel and driver time, and access to consolidation lanes; operating costs affect inventory carrying and labor. Model transit-to-customer, carrier surcharges, and warehousing rates together—select a site where lower facility costs don't introduce disproportionate transit expenses that erode service or margin.

Include clear SLAs for order accuracy, on-time shipment, dock-to-ship lead times, inventory reconciliation cadence, and chargeback rules. Define KPIs (OTD, pick accuracy, cycle count variances), reporting frequency, penalties for missed SLAs, and change-order handling to align expectations and governance.

Assess the 3PL's WMS features (real-time inventory, multi-node allocation), API/EDI capabilities, marketplace connectors, shipping rate shopping, and ability to produce channel-specific packing and returns flows. Request references and sample integration timelines to validate the provider can meet your ramp schedule and data requirements.