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Shop pages & navigation

Filter pages

Also known as: filtered category pages, faceted URLs

Filter pages, in online shop SEO, are category or list pages that get their own URL after a visitor selects filters such as color, size or brand, usually through URL parameters. A few filters can produce a very large number of near-identical URLs.

Why do filter pages matter for SEO?

Google says parameter-based faceted navigation can create nearly infinite URL spaces. Crawlers only recognize the low value of these URLs after many requests. That uses server resources and delays the discovery of new, useful URLs.

Google distinguishes two cases:

  • Filter URLs should not appear in search. Google recommends blocking them with robots.txt or using URL fragments for filters. It calls rel="canonical" and rel="nofollow" generally less effective in the long term.
  • Filter URLs may be indexed. Google recommends the & character to separate parameters, a consistent filter order and a 404 status for combinations without results.

Whether a combination should be indexable depends on whether people search for it (assessment).

How three filters multiply one category into thousands of URLsOwn calculation example: the category /shoes has three filters with 8 colors, 12 sizes and 20 brands. With all three filters set there are 8 × 12 × 20 = 1,920 URLs. If filters may stay empty, it is 9 × 13 × 21 = 2,457, and with three sort orders 7,371. Google describes two paths: URLs meant for search keep a fixed filter order, no duplicate filters and a 404 for empty results; URLs not meant for search are blocked in robots.txt or keep filters in the URL fragment.Category1 page/shoesColor8 values?color=redSize12 values&size=9Brand20 values&brand=…1 URLcategory8 URLswith color96 URLs+ size1,920 URLsall three filtersOWN CALCULATION EXAMPLE8 × 12 × 20 = 1,920 URLs with all three filters setFilters may stay empty: 9 × 13 × 21 = 2,457 URLsPlus 3 sort orders (?sort=price …): 2,457 × 3 = 7,371 URLsEvery other parameter order adds yet another URL.Meant for searchfixed filter order,no duplicate filters,404 for empty resultsNot meant for searchdisallow in robots.txtor keep filters in theURL fragment (#color=red)
Own calculation example. Three filters are enough to turn one category into thousands of URLs. Google describes two approaches, depending on whether the filtered pages are meant for search. Sources: Google Crawling: Managing crawling of faceted navigation URLs; Google Crawling: Optimize your crawl budget.

Example

Text
https://example.com/shoes?color=green&size=42

To keep such URLs from being crawled, robots.txt can disallow them:

robots.txt
user-agent: Googlebot
disallow: /*?*color=
disallow: /*?*size=

Four filters with nine values each and a “not set” option add up to 10,000 URL combinations for a single category. (Calculated example.)

Sources

  1. Managing crawling of faceted navigation URLs – Google Search Centraldevelopers.google.com
  2. Pagination and incremental page loading – Google Search Centraldevelopers.google.com

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