Prioritize WMS functionality and integration (API/EDI), dock doors and throughput capacity, racking and cold-chain availability, measured KPIs (pick/pack accuracy, cycle time), security and insurance, plus value-added services like kitting and returns. Confirm staffing models and peak-season scalability before contracting.

Request the 3PL’s carrier roster and transit-time matrices for parcel and LTL. Map highways and terminal proximity for primary lanes, review historical POD data if available, and test sample shipments. Evaluate zone-fill strategies and regional cross-dock options to reduce last-mile cost and delivery days.

Expect line items for receiving, storage per pallet or cubic foot, pick/pack fees, packing materials, outbound labels, and accessorials. Negotiate clear SLA metrics (accuracy, on-time shipment), fee caps, and service credits tied to KPIs. Ask for bundled rate scenarios to model cost-to-serve at scale.

Develop a phased onboarding plan: data and SKU mapping, WMS setup, ASN/testing of inbound receipts, and parallel order fulfillment for a short period. Schedule capacity planning for labor and docks, run pilot SKUs, validate reporting and billing, and maintain contingency stock during the cutover to limit service impact.