Assess: warehouse layout and racking density, cross-dock and throughput capacity, real-time WMS and API connectivity, bonded/customs facilitation if needed, and proximity to regional carriers. Verify SLA metrics for pick/pack speed, inventory accuracy, and returns handling aligned to your order profile.

Transportation mix (road vs rail vs air) drives landed cost. Choose a 3PL near major trunk routes to reduce truck miles and access competitive carrier pools; negotiate zone-based pricing and minimums reflecting true lane density to optimize per-unit distribution costs.

Prioritize a modern WMS with real-time inventory, API/EDI for marketplace and carrier integrations, barcode/RF picking, order orchestration for split-shipments, and visibility portals for exception management. These reduce errors and accelerate order-to-delivery cycles.

Negotiate clear SLAs for order accuracy, transit times, and inventory reconciliation; pricing cadence and volume tiering; minimum notice for seasonal capacity; liability limits, audit rights, and change control for service add-ons to avoid hidden fees.

Request historical throughput data, floorplan flexibility, temp labor ramp procedures, and lead times for additional storage. Confirm peak handling protocols, access to adjacent space or shared cross-dock capacity, and contractual options for short-term capacity bursts.