Back in Stock Alert Scraper: Products, Sizes, Colours

Description and use

An Apify-based scraper automatically checks product and variant stock status, alerting when items become available.

Problem

Detect when a product or a specific variant (size/colour) changes from out of stock to in stock to trigger alerts.

Outcome

The scraper processed 10,645 product rows in October 2026, identifying 8,344 true inStock, 406 false, and 1,895 null entries. It correctly reported a real size restock on Zalando and demonstrated variant-level alerts for a John Lewis product.

Workflow

• 1. Configure Apify actor with monitorMode:true and onlyChanges:true.
• 2. Run actor hourly to scrape product pages and capture inStock, availability, stockQty, and variant details.
• 3. Actor stores each run’s data and diffs with the previous run.
• 4. Parse monitor output: if changeType is back-in-stock, emit product-level alert; if changeType is changed with variant-stock-changed, emit variant-level alert.
• 5. Use provided Python snippet to format and send alerts.
• 6. Optionally filter out null inStock values and treat only known false→true flips as restocks.

Evidence

Only a known false followed by a known true is a restock.

Source

Run the actor with monitorMode: true and onlyChanges: true on a schedule.

Source

When one variant flips, the product’s changeType is changed, changes contains variant-stock-changed, and the variant appears in changedVariants with previousInStock and inStock.

Source