Faceted Navigation & SEO
Faceted navigation is the set of filters in online shops that let users narrow product listings by attributes such as colour, size or price. Because every filter combination can technically generate its own URL, faceted navigation carries a high risk of duplicate content and a bloated crawl budget unless it is controlled carefully.
In practice
Usually only a selection of filter combinations with sufficient search volume ("red trainers size 42", for example) is released for indexing, while the rest are excluded via canonical tag, robots meta tag or parameter handling. It also matters that filtered pages stay crawlable even when they are not meant to be indexed, so that internal link equity is not lost. Close coordination between the SEO and development teams is essential here, because filter logic is often configured centrally in the shop system.