Definition
Faceted navigation is the filter system in webshops and catalogues that lets visitors refine a product list by attributes such as brand, price, colour, size and material, and sort the results. Every combination of filters usually produces its own URL, such as /shoes?brand=nike&colour=black&size=43. For visitors it is indispensable; for search engines it is one of the biggest sources of duplicates and wasted crawl budget.
The problem is mathematical. Ten filters with five values each produce millions of combinations, and every combination is technically a separate page with almost the same products. Googlebot tries to crawl them all, keeps finding the same thing, and never gets round to the pages that matter. At the same time, all those URLs dilute the authority of the category page and thousands of near-duplicates end up in the index.
The skill is distinguishing facets with search demand from facets without. 'Nike running shoes' and 'black running shoes' are searched for and deserve an indexable, optimised page with its own title, text and canonical. 'Running shoes sorted by price ascending, size 43, price 80 to 120 euros' is searched by nobody and belongs outside the index. Search data and Search Console show which combinations have demand.
Technical tools, in increasing weight: a canonical from filter combinations to the main category or the indexable facet; noindex on combinations without demand; robots.txt blocks on parameters such as sort and page size (carefully, because blocked URLs can still get indexed through links); and rendering low-value filters without crawlable links, for example through JavaScript or a form. Combine that with a consistent parameter order so the same selection always gets the same URL.
Well-configured facets are also an opportunity: every indexable filter page is a long-tail landing page with real products and its own intent. For webshops, Traze inventories which facet combinations have search demand, writes unique intros, titles and FAQs for them and checks in the technical scan that the remaining combinations are correctly excluded.