Multi-Vendor Inventory Sync

Arka Designs, a jewelry retailer, sells diamonds sourced from third-party suppliers. Their inventory isn't sitting in a warehouse. It's virtual: they display supplier inventory on their Shopify store and fulfill orders by purchasing from the supplier when a customer buys.

The old process was brutal: download CSV from supplier portal, manually compare with Shopify, update prices and availability one by one. With 5,000+ SKUs and prices changing daily based on diamond market conditions, this took 3-4 hours every day.

Worse, inventory mismatches meant selling diamonds that were already gone. Customers would order, then get a 'sorry, out of stock' email days later. This was killing their reputation and conversion rate.

I built an automated pipeline that runs every 6 hours via EventBridge. A Lambda function pulls the supplier's full inventory feed, normalizes the data (their format is messy), and compares against current Shopify listings.

The sync is intelligent: it only pushes changes, not the full catalog. Price changed? Update. Sold elsewhere? Mark unavailable. New stone? Create listing with generated description. This keeps API calls minimal and Shopify happy.

We added monitoring to catch anomalies. If more than 10% of inventory suddenly disappears, the sync pauses and alerts for manual review. This prevents supplier feed errors from nuking the entire store.