URL Parameters are an integral part of URL structures. Although they are an invaluable asset in the hands of seasoned SEO professionals, query strings often present serious challenges for your website rankings.

In this guide you’ll find the most common SEO issues to watch out for when working with URL parameters.

URL parameters (known also as “query strings” or “URL query parameters”) are elements inserted in your Urls to help you filter and organize content or track information on your website.

In short, URL parameters are a way to pass information about a click using the URL itself.

To identify a URL parameter, refer to the portion of the URL that comes after a question mark (?). URL parameters are made of a key and a value, separated by an equal sign (=). Multiple parameters are each then separated by an ampersand (&).

A URL string with parameters looks like this:

 https//www.domain.com/page?key1=value1&key2=value2 

Key1: first variable name 
Key2: second variable name
Value1: first property value
Value2: second property value
? : query string begins
= : value separator
& : parameter separator

URL parameters are commonly used to sort content on a page, making it easier for users to navigate products in an online store. These query strings allow users to order a page according to specific filters, and to view only a set amount of items per page.  

Query strings of tracking parameters are equally common. They’re often used by digital marketers to monitor where traffic comes from, so they can determine whether their latest investment in social, ad campaign, or newsletter was successful. 

According to Google Developers, there are two types of URL parameters:

1. Content-modifying parameters (active): parameters that will modify the content displayed on the page

• e.g. to send a user directly to a specific product called ‘xyz’

http://domain.com?productid=xyz

2. Tracking parameters (passive) for advanced tracking: parameters that will pass information about the click — i.e. which network it came from, which campaign or ad group etc. — but won’t change the content on the page. 

This information will be clearly recorded in a tracking template and will include valuable data for you to evaluate your recent marketing investments.

• e.g. to track traffic from your newsletter 

https://www.domain.com/?utm_source=newsletter&utm_medium=email

• e.g. to collect campaign data with custom URLs

https://www.domain.com/?utm_source=twitter&utm_medium=tweet&utm_campaign=summer-sale

It might seem fairly simple to manage, but there is a correct and an incorrect way to use URL parameters, which we’ll discuss shortly after some examples.

Common uses for URL parameters include:

Most SEO-friendly advice for URL structuring suggests keeping away from URL parameters as much as possible. This is because, however useful URLs parameters might be, they tend to slow down web crawlers as they eat up a good chunk of crawl budget.

Poorly structured, passive URL parameters that do not change the content on the page (such as session IDs, UTM codes and affiliate IDs) hold the potential to create endless URLs with non-unique content. 

The most common SEO issues caused by URL parameters are:

1. Duplicate content: Since every URL is treated by search engines as an independent page, multiple versions of the same page created by a URL parameter might be considered duplicate content. This is because a page reordered according to a URL parameter is often very similar to the original page, while some parameters might return the exact same content as the original.

2. Loss in crawl budget: Keeping a simple URL structure is part of the basics for URL optimization. Complex URLs with multiple parameters create many different URLs that point to identical (or similar) content. According to Google Developers, crawlers might decide to avoid “wasting” bandwidth indexing all content on the website, mark it as low-quality and move on to the next one. 

3. Keyword cannibalization: Filtered versions of the original URL target the same keyword group. This leads to various pages competing for the same rankings, which may lead crawlers to decide that the filtered pages do not add any real value for the users.

4. Diluted ranking signals: With multiple URLs pointing to the same content, links and social shares might point to any parameterized version of the page. This can further confuse crawlers, who won’t understand which of the competing pages should be ranking for the search query.

5. Poor URL readability: When optimizing URL structure, we want the URL to be straightforward and understandable. A long string of code and numbers hardly fits the bill. A parameterized URL is virtually unreadable for users. When displayed in the SERPs or in a newsletter or on social media, the parameterized URL looks spammy and untrustworthy, making it less likely for users to click on and share the page.

The majority of the aforementioned SEO issues points to one main cause: crawling and indexing all parameterized URLs. But thankfully, webmasters are not powerless against the endless creation of new URLs via parameters.

At the core of good URL parameter handling, we find proper tagging.

Please note: SEO issues arise when URLs containing parameters display duplicate, non-unique content, i.e. those generated by passive URL parameters. These links — and only these links — should not be indexed.

Your crawl budget is the number of pages bots will crawl on your site before moving on to the next one. Every website has a different crawl budget, and you should always make sure yours is not being wasted.

Unfortunately, having many crawlable, low-value URLs — such as parameterized URLs created from faceted navigations — is a waste of crawl budget.

If your website has many parameter-based URLs, it is important to signal to crawlers which pages not to index, and to consistently link to the static, non-parameterized page. 

For example, here are a few parameterized URLs from an online shoe store: 

In this case, be careful and consistently link only to the static page and never to the versions with parameters. In this way you will avoid sending inconsistent signals to search engines as to which version of the page to index.

Once you decided on which static page should be indexed, remember to canonicalize it. Set up canonical tags on the parameterized URLs, referencing the preferred URL. 

If you create parameters to help users navigate your online shop landing page for shoes, all URL variations should include the canonical tag identifying the main landing page as the canonical page. So for example:

• /shoes/women-shoes/
• /shoes/women-shoes?color=blue
• /shoes/women-shoes?type=high-heels

In this case, the three URLs above are “related” to the non-parameterized women shoes landing page. This will send a signal to crawlers that only the main landing page is to be indexed and not the parameterized URLs. 

URL parameters intended to sort and filter can potentially create endless URLs with non-unique content. You can choose to block crawlers from accessing these sections of your website by using the disallow tag.

Blocking crawlers, like Googlebot, from crawling parameterized duplicate content means controlling what they can access on your website via robots.txt. The robots.txt file is checked by bots before crawling a website, thus making it a great point to start when optimizing your parameterized URLs. 

The following robots.txt file will disallow any URLs featuring a question mark:

Disallow:/*?tag=*

This disallow tag will block all URL parameters from being crawled by search engines. Before choosing this option, make sure no other portion of your URL structure uses parameters, or those will be blocked as well.

You might need to carry out a crawl yourself to locate all URLs containing a question mark (?).  

This falls into the wider discussion about dynamic vs static URLs. Rewriting dynamic pages as static ones improves the URL structure of the website.

However, especially if the parameterized URLs are currently indexed, you should take the time not only to rewrite the URLs but also to redirect those pages to their corresponding new static locations. 

Google Developers also suggest to: 

• remove unnecessary parameters, but maintain a dynamic-looking URL
• create static content that is equivalent to the original dynamic content
• limit the dynamic/static rewrites to those that will help you remove unnecessary parameters.

As it must be clear by now, handling URL parameters is a complex task and you might need some help with it. When setting up a site audit with Semrush, you can save yourself a headache by identifying early on all URL parameters to avoid crawling. 

In the Site Audit tool settings, you’ll find a dedicated step (Remove URL parameters) where you can list the parameters URLs to ignore during a crawl (UTMs, page, language etc.). 
 
This is useful because, as we mentioned before, not all parameterized URLs need to be crawled and indexed. Content-modifying parameters do not usually cause duplicate content and other SEO issues so having them indexed will add value to your website. 

If you already have a project set up in Semrush, you can still change your URL parameter settings by clicking on the gear icon.

Parameterized URLs make it easier to modify or track content, so it’s worth incorporating them when you need to. You’ll need to let web crawlers know when to and when not to index specific URLs with parameters, and to highlight the version of the page that is the most valuable. 

Take your time and decide which parameterized URLs shouldn’t be indexed. With time, web crawlers will better understand how to navigate and value your site’s pages.