Prioritize order accuracy, scalable pick-and-pack capacity, integrated WMS/OMS connectivity, returns handling, and value-added services (kitting, light assembly). Verify SLA metrics for pick-to-ship times and peak-season scalability; request KPIs and references for similar product profiles.

Carrier access affects lane options and pricing: proximity to major ports and arterial roads shortens drayage and line-haul times, while local courier partnerships improve last-mile reliability. Evaluate LTL/FTL service density and typical transit windows for your target markets.

Compare storage rate structures (pallet vs. cubic), inbound receiving fees, pick/pack pricing tiers, minimum monthly charges, and surcharges for seasonal peaks or returns handling. Include labor productivity assumptions and any integration/setup fees in your TCO model.

Look for real-time WMS with API-driven integrations to your storefront, ERP, and carrier platforms, EDI or RESTful endpoints for order flow, and dashboard/reporting for inventory, exceptions, and SLA compliance. Ask about batch reconciliation and audit trails.

Define a time-bound pilot with clear KPIs (OTD, accuracy, cost per order), sample SKUs that represent complexity, and agreed change-control processes. Include penalty/bonus clauses based on measurable SLAs and require visibility into labor and process mapping during the trial.