Inventory numbers go wrong quietly. A sync fails, an import loads the wrong sheet, a fulfilment double-counts, and the first sign is that a product stopped selling. Driftwatch downloads your full catalog from Shopify every night and compares it against what it recorded yesterday. It reports what changed, what went negative, and what moved in bulk, then stays silent until something else drifts. It asks for three read permissions and no write permission at all.

• Nightly full-catalog check against Shopify's own data
• Alerts on negative stock, duplicate SKUs and missing product fields
• Detects bulk changes: hundreds of items moving within minutes
• One email per run, and nothing at all when nothing has changed
• Read-only by design: no write permission, so it cannot alter your store