Assess WMS capability and integrations, API connectivity to marketplaces and carriers, real-time inventory accuracy, slotting and throughput for peak volume, and support for value-add services (kitting, labeling, temp control). Require performance reporting and a roadmap for technology upgrades.

Compare fixed vs. variable fees: receiving, storage per pallet/SKU, pick-and-pack rates, kitting, returns processing, and outbound freight access fees. Factor minimums, billing cadence, chargeback policies, and how labor surcharges apply during peaks.

Proximity to highways and intermodal hubs shortens line-haul and enables more favorable zonal pricing. Evaluate parcel and LTL carrier coverage, frequency of pickups, and the 3PL's ability to consolidate or zone-skip to reduce last-mile cost and transit days.

Require SLAs and regular reporting for OTIF, order cycle time, inventory accuracy, dock-to-stock times, pick/pack error rates, and return processing times. Include escalation paths, remedies for missed SLAs, and visibility into labor productivity metrics.

Confirm access to additional space or satellite sites, labor ramp plans, flexible pricing tiers for volume spikes, and cross-dock capabilities to accelerate throughput. Verify quick onboarding timelines, contingency plans for carrier disruptions, and modular service options.