Require clear KPIs and reporting: order cycle time, on-time shipment rate, inventory accuracy, pick-and-pack error rate, and average dwell time. Confirm WMS functionality, API/EDI connectivity, SLA penalties, scalability for peak seasons, and documentation for bonded/temperature-controlled handling.

Model total landed cost per SKU including storage per pallet/day, unit pick-and-pack cost, inbound handling, outbound freight rates, fuel surcharges, and return processing. Include inventory carrying costs and potential transit time savings to calculate service-level trade-offs against per-unit fees.

Validate bonded status, customs brokerage capability, temperature-control certifications, local labor compliance, insurance coverages, and security protocols. Confirm clearance times at nearby ports and the 3PL’s experience handling cross-border documentation and audits.

Look for real-time inventory visibility via WMS with API access, order orchestration tools, EDI for trading partners, shipment tracking integration with carriers, and return management workflows. Ensure the 3PL provides dashboards and automated reporting to measure SLAs and exceptions.