Multichannel selling doesn’t break because you’re bad at ecommerce — it breaks because every channel acts like its own source of truth. This playbook gives you the exact system to run Amazon, eBay, Shopify and Etsy from one operations hub instead of five disconnected ones: inventory sync rules, a “create once, publish everywhere” listing workflow, customer message triage, a channel-expansion checklist, and a real profitability tracker. Includes 20+ ready-to-use AI prompts and a 7-day implementation plan.