Bots on product filters: why WooCommerce and PrestaShop slow down without more visits

If your WooCommerce or PrestaShop store has started responding more slowly, with high CPU usage and PHP processes constantly at their limit, but the number of orders hasn't changed, there's another suspect to check before upgrading your hosting plan: bot traffic exploring product filters.

This is highlighted by a technical analysis published on 5 November 2026 on the Serverplan blog, which describes a phenomenon observed across multiple managed WooCommerce and PrestaShop installations. In one of the monitored cases, over 50,000 requests were recorded to nearly as many distinct URLs generated by filter combinations.

Why caching isn't enough

Each filter for colour, size, brand or price produces a different URL: /shop/?filter_color=black&min_price=100 is not the same page as /shop/?filter_color=black&filter_brand=nike. When a crawler requests thousands of these combinations, most generate a cache miss: PHP must re-execute the query and interrogate MySQL from scratch. On PrestaShop the affected module is typically ps_facetedsearch (Faceted Search), on WooCommerce the issue appears with native filters or plugins like YITH WooCommerce Ajax Product Filter.

What Google says and what you can verify

The problem isn't specific to any one provider. In its developer documentation, Google notes that crawling faceted navigation URLs tends to consume large amounts of server computational resources, due to the number of URLs and the operations required to generate those pages, and recommends using robots.txt to prevent crawling of faceted navigation URLs, because there's often no good reason to allow it: it consumes server resources without appreciable benefit.

On the scale of the phenomenon, Cloudflare Radar's most recent data (October 2026) shows non-AI bots at 54.6% of requests and AI crawlers at 6.3%, against 35% human traffic: a proportion consistent with what Serverplan reported for September 2026.

Practical checklist before upgrading resources

Check	How to do it	What it tells you
Slow pages vs normal	Compare response times between catalogue and filtered pages	Isolate the problem
Cache status	Check whether filtered pages are served from cache	Understand cache misses
Access logs	Search for parameters like filter_color, yith_wcan, q=, order	Quantify combinations
Profiler	Query Monitor (WordPress) or PrestaShop profiler, in test environment	Measure SQL queries and PHP times
robots.txt	Block filter patterns unnecessary for indexation	Reduce crawler scanning

Anyone running an online shop experiencing these symptoms should check with their developer which filter combinations are actually needed for SEO and which can be excluded from crawling, before changing the hosting plan.