Distributed Shopify Inventory Sync: Architecture Guide for Scale

Keeping inventory accurate across Shopify, warehouses, and marketplaces sounds simple. At scale, it is one of the hardest engineering problems in ecommerce. A single API call after each sale works fine at 200 orders a day. At 20,000 concurrent transactions, it collapses. Here is what breaks first: Overselling when two orders hit the same SKU simultaneously Stale counts when a warehouse update takes minutes to reflect Silent failures when a sync call times out with no retry Duplicate decrements w