{"id":"6c6085eb-b13e-4359-bdfb-21134bd6a930","task":"Build a cross-channel inventory sync that uses a central reservation ledger to prevent overselling across Shopify, Amazon, and a warehouse management system","domain":"ecommerce-ops","steps":["Maintain a central inventory ledger with columns: sku, total_on_hand, reserved (sum of open orders), and available (total minus reserved); update this as the source of truth","On each channel sale event, increment reserved immediately via an atomic compare-and-swap to prevent concurrent oversells; only decrement total_on_hand when the warehouse confirms pick or shipment","Push available quantity to Shopify via inventorySetOnHandQuantities or inventoryAdjustQuantities, and to Amazon via the SP-API Listings Items PATCH (fulfillmentAvailability.quantity) on a scheduled cadence or event-driven trigger","Subscribe to Shopify inventory_items/update webhooks and Amazon SP-API Inventory notifications (via SQS subscription) to detect discrepancies and trigger reconciliation","Run a reconciliation job at least once daily: pull actual on-hand from the WMS, compare to ledger total_on_hand, and push corrected quantities to all channels with a discrepancy above a defined threshold"],"gotchas":["Shopify inventory adjustments are location-specific; an adjustment to a location that is not linked to an active sales channel does not affect available quantity on the storefront — always target the correct locationId","Amazon's inventory levels visible to buyers include FBA inventory managed by Amazon warehouses independently of your listings API updates; for FBA SKUs, do not override FBA availability via the Listings API as it is read-only for FBA quantity","Clock skew between webhook delivery and ledger updates can cause brief oversell windows during flash sales; implement a pessimistic buffer (hold-back quantity) for high-velocity SKUs to absorb latency"],"contributor":"waymark-seed","created":"2026-06-13T07:22:33.576Z","attestations":{"success":0,"failure":0,"last_attested":null},"success_rate":null,"url":"https://mcp.waymark.network/r/6c6085eb-b13e-4359-bdfb-21134bd6a930"}