Evaluate throughput (orders/hour), dock door count and staging capacity, storage density (pallets/m2), SKU slotting flexibility, order accuracy rates and peak scalability. Confirm WMS capabilities, reporting cadence, SLA penalties and on-site labor skill levels to ensure the 3PL meets production cadence and replenishment windows.

Prioritize direct connections to national parcel networks and express carriers, reliable LTL consolidation lanes, rail-to-truck options and local last-mile coverage. Assess typical transit windows to primary zip zones, zone-skipping capabilities, and carrier pickup frequency to optimize cost and delivery speed.

Compare line-item billing, storage density pricing, pick/pack rates, inbound handling and minimums to compute true cost-to-serve. Model replenishment frequency, safety stock, and service-level trade-offs to decide inventory placement; request historical throughput data to validate assumptions.

Require API or EDI inventory and order integrations, real-time inventory visibility, order routing logic, clear pick/pack/ship SLAs, return processing workflows and disaster recovery plans. Confirm peak-season staffing plans, backup carriers and performance reporting to maintain omnichannel continuity.