URL parameters, or query strings, are the part of a URL after the question mark, written as key=value pairs joined by ampersands. Sites use them to filter and sort lists, paginate, track campaigns and store session state. Because each combination is a distinct URL to a crawler, uncontrolled parameters can create large numbers of duplicate or near-duplicate pages and waste crawl effort.
Types of parameters
It helps to sort parameters by what they do to the content. Some change it meaningfully, such as a page number or a category filter. Others only reorder it, and some change nothing at all, such as tracking tags and session IDs.
- Content-changing: ?category=crm, ?page=2, ?lang=de
- Reordering: ?sort=price-asc, ?view=grid
- Tracking: ?utm_source=newsletter, ?ref=partner
- Session or state: ?sessionid=abc123
How to manage them
Google retired the URL Parameters tool in Search Console in 2022, so control now happens on your site. Point parameter URLs that duplicate a clean page to it with a canonical tag. Keep tracking and session parameters out of internal links, so crawlers mostly find them only from external sources. Use robots.txt to block parameter patterns that should never be crawled, accepting that blocked URLs cannot pass canonical signals.
Keep parameter order consistent, so ?a=1&b=2 and ?b=2&a=1 are not both linked, and avoid empty or default-value parameters in links.
<!-- On https://example.com/integrations?sort=popular -->
<link rel="canonical" href="https://example.com/integrations">When a parameter page should be indexed
Some filtered views match real searches, such as integrations for a specific CRM. Those are often better served by a clean, static path with its own title and copy than by a parameter URL, so you can link to them and optimize them deliberately.
Example
Tracking parameters leaking into the index
Lanternhook, an email deliverability tool, links internally to its pricing page with ?ref=nav and ?ref=footer to measure clicks. Search Console's Page indexing report shows several versions of the pricing URL discovered. Switching to event-based click tracking and removing the parameters from internal links consolidates signals on one URL.
Common mistakes
Blocking parameters you also canonicalize
If robots.txt blocks a URL, Google cannot see its canonical tag. Choose one method per pattern.
Using UTM tags on internal links
UTMs are for external campaigns. On internal links they create duplicate URLs and overwrite the original session source in analytics.
Questions
Parameters themselves are fine. Problems come from duplicates splitting signals and from crawlers spending time on endless combinations instead of important pages.
