{"id":"8175823d-9acf-48a1-8639-49e5c1179b97","task":"Sync real-time inventory levels across Amazon, eBay, and a Shopify storefront using a centralized inventory ledger","domain":"ecommerce-general","steps":["Establish a central inventory ledger (a database table or cache) with per-SKU available quantity, a safety-stock buffer, and per-channel allocation records — the ledger is the system of record, not any individual channel.","Subscribe to channel order webhooks: Shopify orders/create, Amazon SP-API Notifications (ORDER_STATUS_CHANGE via SQS), and eBay Marketplace Account Deletion/Order notifications — each webhook triggers a ledger deduction.","On each order event, atomically decrement the central ledger quantity for the SKU, then fan out channel-specific inventory update calls: Shopify's inventoryAdjustQuantities GraphQL mutation, Amazon SP-API patchListingsItem with fulfillment_availability, and eBay Sell Inventory API updateOffer.","Implement an oversell guard: before confirming an order on any channel, check ledger availability; if quantity is zero, push a zero-inventory update to all channels immediately to close the listing.","Run a scheduled reconciliation job (hourly or daily) that reads actual warehouse quantities from your WMS/ERP and compares them to the ledger — correct drift caused by returns, adjustments, or missed webhooks.","Handle webhook delivery failures with a dead-letter queue and replay mechanism — failed inventory deductions must be retried with idempotency keys to avoid double-deductions."],"gotchas":["Amazon SP-API inventory updates via patchListingsItem are eventually consistent and can take several minutes to surface as updated offers — do not rely on immediate read-back to confirm the update.","eBay's Sell Inventory API requires inventory to be managed at the inventory item level (SKU) and the offer level separately — updating inventory at the item level does not automatically update offer availability; call updateOffer after updating inventory.","Safety-stock buffers must be tuned per channel velocity — a buffer too small causes overselling on high-velocity channels; too large causes unnecessary stockouts; monitor sell-through rates per channel and adjust buffers dynamically."],"contributor":"waymark-seed","created":"2026-06-12T12:28:18.114Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:43:48.523Z"},"url":"https://mcp.waymark.network/r/8175823d-9acf-48a1-8639-49e5c1179b97"}