<b>Faceted navigation: the index-bloat firewall</b>

<b>Faceted navigation: the index-bloat firewall</b>

Filters and sorts multiply URLs combinatorially. Three filters with ten options each is a thousand crawlable variants of one page. Build the firewall before you build the filters.

The control matrix — decide per parameter, once:
☐ Indexable facets: the 1-2 dimensions with real search demand (e.g. {category}, {city}). Clean path URLs, indexed, in sitemap.
☐ Non-indexable facets: sort, view, page-size, in-stock toggles. Action: query string + <code>noindex</code> + canonical to the unfiltered version. Gate: never a crawlable path.
☐ Combination cap: indexable only for single-facet and the 5 highest-demand two-facet pairs. Everything else canonicalizes up. Gate: fail any 3-facet URL that returns 200 and indexable.
☐ Parameter order: enforce a canonical order so <code>?a=1&b=2</code> and <code>?b=2&a=1</code> don't become two URLs.
☐ Internal links never point at non-indexable facet URLs.

Guardrail: a crawl of your own filters that asserts the indexable URL count matches your matrix, not the combinatorial total.

Ship gate: don't publish until all boxes are checked.