I tested monitoring on my own shop: alerts about changes that never happened

I run an online shop, Redder.ro. In October I put one of its product pages under monitoring as a test. I had not changed anything on that page for several weeks: no price, no stock, no text. Nothing had been sold. Still, I received alerts saying it had changed.

What the alert reported

One of the alerts, from a well-known monitoring service, said the displayed stock had dropped from 17 to 12 units. It also said that two Kumaniok vodka variants and a price of 44.00 lei had appeared in the related-products section, while two Pshenoff variants had disappeared. 24 changes in total.

None of them was a change I had made. The alert sounded precise and confident, with numbers and product names. That is exactly what makes it dangerous: a shop owner who does not know what happens behind the scenes may believe it.

Where changes that do not exist come from

A product page is not a fixed document. Many shops, including those built on WooCommerce, show a list of related or recommended products under the product, picked and reshuffled on every page load. Two visitors opening the page in the same minute can see different products in that list.

A monitor that compares the whole page, as text or as an image, sees different names and prices in that area every time. For the monitor, the page has changed. If an AI model then writes a summary of the difference, the result can be a coherent story about a change that never happened.

Other elements can vary the same way: counters, rotating banners, dates and times shown on the page. That is exactly what the “stock” in the alert above was. The page showed “1986 in stock” the whole time. The number 17, then 12, then 14 was a visitor counter with an eye icon, shown by the shop theme under the wishlist button. The AI that wrote the summary took it for the stock.

We had the same problem

I noticed this because OmniWatchGuard, the app I build, made the same mistake on the same page. On 7 October, our test monitor for the Redder.ro product was sending alerts about related products being added and removed.

We fixed it the same day, in two ways:

• Before comparing, lists of related, recommended or recently viewed products are removed from the page. On a category page, where the product list is the actual content, they stay.
• The AI model that analyses the difference has an extra rule: if only such lists changed, the change is noise and no alert is sent.

The change is listed in our changelog. We do not claim to have removed every false alert: any page can have other parts that change by themselves.

How to avoid false alerts, with any tool

• Watch one element, not the whole page. If you care about the price, monitor only the price area, with a CSS selector or a monitor type made for prices.
• Prefer tools that read structured data. Many shops also publish price and stock in a format for search engines (JSON-LD). Related products do not appear there.
• Open the page twice. If a part looks different on the second load without anyone changing anything, that part will cause false alerts.
• Set a threshold. For prices, alerting only above a certain percentage or only on a drop removes many worthless messages.
• Check the first alert. Before relying on a new monitor, compare the first reported change with the real page.

Conclusion

A monitoring alert is only worth the trust you can put in it. If you often get changes you cannot find on the page, it is not your fault: the tool is also comparing the parts that change by themselves. It is worth choosing a tool that ignores them and watching only what matters to you.