URL parameters are widely used for page variations and campaign tracking, but they have to be managed properly to prevent crawlability and duplicate content issues.
In this guide, we’ll explain what URL parameters are, how they work, when they’re useful, and how to manage them properly for SEO.
Let’s get started.
What Are URL Parameters?
URL parameters are extra pieces of information added to the end of a URL that tell a website how to customize the content, filter results, or track browsing sessions.
Here’s a simple URL parameter example that would be used to filter results:
URL parameters are just one part of a full URL, which typically includes a scheme, domain name, top-level domain, and path.
URL Parameter Structure
URL parameters appear after a question mark (?) and include key-value pairs that are separated by one or more ampersands (&), which means:
- Everything before the question mark (?) is a standard URL
- All parameters come after the question mark (?)
- Each parameter is written as a key and value separated by an equal sign (category=shoes)
- Multiple parameters are separated with an ampersand (&)
Multiple URL parameters combined. And what you see on the page can adjust based on those values.
URL Parameters vs. Query Strings
The terms “URL parameters” and “query strings” are often used interchangeably, which is perfectly fine in most contexts.
However, there’s a subtle technical distinction between URL parameters and query strings.
URL parameters are the individual key-value pairs, such as:
category=shoes
color=blue
size=9
A query string is the entire string of parameters, including the question mark and ampersands:
?category=shoes&color=blue&size=9
Feel free to use either the term URL parameters or query strings in your own conversations. Most developers understand that they essentially refer to the same concept.
How Are URL Parameters Used?
URL parameters are used to enhance a website’s functionality and the user experience.
Below are some of the most common use cases for URL parameters:
- Filtering and sorting content: You can use URL parameters to filter or sort content dynamically without users needing to reload the entire page. This is especially useful for ecommerce websites with numerous product categories and variations. Or any site that needs to help users narrow down large collections of items.
- Personalization: Websites can use parameters to tailor experiences, like showing users region-specific pages based on their location (?region=us) or displaying content in their preferred language (?lang=en). There are better alternatives for SEO-friendly localization, which we’ll cover later.
- Pagination: URL parameters help display large sets of content across multiple pages (?page=2, ?page=3, ?page=4, and so on) to enable users to navigate through them. This is especially useful for websites with large collections, such as blog posts and product listings.
- Search functionality: URL parameters are also used in a website’s search functionality. When a user submits a search query, the query is appended to the URL (?search=running+shoes), which allows the website to display relevant search results.
- Session management: Some websites use URL parameters to maintain session information and track user activity across multiple pages (?sessionid=xyz123). However, cookies have largely replaced this approach.
- Campaign tracking and analytics: Marketers use parameters like “utm_source=facebook” or “utm_campaign=summer_sale” to see where traffic comes from when evaluating campaign performance
What Are the Main Types of URL Query Parameters?
URL parameters can be broadly categorized into two types: active and passive.
Active Parameters
Active parameters directly affect the content or behavior of a webpage.
When active parameters appear in a URL, the website uses these values to change what the page shows or how it functions to create a dynamic and interactive experience tailored to the user’s needs.
Common examples of active parameters include:
- Filtering product listings
- Loading a specific page from a paginated series
- Displaying a region-specific page
Passive Parameters
Passive parameters don’t change the visible content of a page but instead work behind the scenes to support functions like tracking user behavior or managing sessions.
Basically, passive parameters help developers and marketers collect data and better manage important processes.
Typical uses for passive parameters include:
- Monitoring traffic sources
- Identifying user sessions
How Do Parameters in URLs Affect SEO?
URL parameters can negatively affect SEO performance and AI visibility largely because they result in many pages with similar content.
The most common search visibility issues caused by URL parameters include:
- Duplicate content: Parameters can create multiple versions of the same page. For example, “?sort=asc” and “?sort=desc” may display the same content in a different order. Search engines and AI systems can struggle to determine which version to prioritize, reducing overall visibility.
- Crawl budget waste: Search engine and AI crawlers only allocate a certain amount of time and resources to crawling a website in a given timeframe. If your site generates numerous URLs with parameters that lead to similar content, website crawlers might waste time on these variations instead of discovering new, unique content.
- Keyword cannibalization: Multiple URLs with different parameters often target the same group of queries. This means your pages are essentially competing against each other in search results. This internal competition can prevent any single page from performing well in traditional and AI search.
- Diluted ranking signals: When external and internal links point to multiple parameterized versions of the same page, link equity can be split across those URLs instead of being consolidated on one canonical version. This weakens the main page’s overall search performance potential.
Key Considerations When Using URL Parameters
URL parameters require careful planning and management because of how they can impact your search visibility.
So, keep the following considerations in mind when using URL parameters on your website:
Parameter Order Matters
Search engines and AI systems can treat URLs with the same parameters in different orders as separate pages, even when they display identical content.
For example, “?color=blue&size=9” and “?size=9&color=blue” may be seen as distinct URLs. This creates even more duplicate content that can affect search performance.
Practically speaking, your website’s technical implementation will take care of maintaining a consistent parameter order most of the time. For campaigns that involve manually creating URL parameters, align your team on the correct order.
Parameters Lead to Performance Trade-Offs
URLs with parameters often bypass caching mechanisms, which leads to slower load times as servers fetch fresh content.
If your parameters don’t significantly change the content, consider whether the functionality justifies the performance cost.
5 SEO Best Practices for Using URL Parameters
To mitigate search visibility challenges that URL parameters can create, follow these best practices:
1. Add Canonical Tags
All parameterized URLs should include a canonical tag (a type of HTML snippet) identifying the page that doesn’t contain parameters as the main page.
Here’s what a canonical tag looks like:
<link rel="canonical" href="https://www.yourdomain.com/your-main-page" />
Canonical tags tell search engines which URLs should be indexed (stored in a database) for ranking. Which consolidates link equity to the main page and prevents issues with duplicate content.
Plus, search engines will prioritize crawling canonical pages over the parameterized variations as time passes, resulting in crawl efficiency for your site.
Clear canonical signals also help your preferred page show in AI-powered search systems.
Adding canonical tags is especially important for sites with extensive filtering options, such as:
- Ecommerce sites with filters for color, size, brand, price, etc.
- Real estate sites with filters for location, price range, amenities, etc.
- Job boards with multiple filter combinations for role, experience, location, etc.
- Any site where similar content is accessible through many parameter combinations
Implementing canonical tags is relatively straightforward. Work with your developer to add this line to the <head> section of your parameterized pages and to the canonical version (just replace the example URL with the main page URL you want to specify):
<link rel="canonical" href="https://www.yourdomain.com/your-main-page" />
2. Block URLs Containing Parameters with Robots.txt
In some cases, you may need to prevent search engines from crawling URLs with specific parameters by configuring your robots.txt file.
Bots check the robots.txt file before they crawl your website. And they generally follow its instructions on which pages to avoid crawling. Consider these scenarios:
- You have parameters that generate near-infinite URLs with little unique content
- You’re experiencing crawl budget issues, and search engines aren’t able to crawl all of your important pages due to the sheer number of URLs with parameters
In each of these cases, blocking certain parameters can significantly improve how efficiently bots can crawl your website. And prioritize your most important content.
To view Google’s crawl activity and identify problematic parameters, go to Google Search Console (GSC) and navigate to “Settings.”
Find the “Crawl stats” report and click “Open Report.”
Scroll to “By file type” and click “HTML” to see Google’s crawl activity on your site.
Under “Examples,” look for recurring parameterized URLs that may be wasting your crawl budget.
Once you’ve identified the problematic parameters, block them in your robots.txt file. For example, the below block tells crawlers not to crawl URLs containing “?sort=,” which saves crawl budget for more important content:
User-agent: *
Disallow: /*?sort=
3. Avoid URL Parameters for Localization
If your site serves customers in different regions and/or languages, it’s best to avoid using URL parameters for localization because they aren’t very user-friendly and can cause problems with your search results.
Plus, Google has explicitly stated that URL parameters shouldn’t be used for localization.
It’s better to use dedicated URLs for each region. This approach is more user-friendly and provides clearer geotargeting signals for search engines.
Common URL structure for region-specific pages include:
- Subdirectories (e.g., example.com/fr/)
- Subdomains (e.g., fr.example.com)
- Separate country-code top-level domains (e.g., example.co.fr)
4. Use Consistent Internal Linking
Internal links to pages within your own site should point to the clean, canonical version of each page—not parameterized variations.
Consistently linking to canonical pages consolidates link equity and sends clear signals to search engines and AI systems about which page to prioritize in search results.
5. Exclude Parameterized URLs from Your Audits
Excluding parameterized URLs from SEO audits keeps the audit focused on your core website content.
When using Semrush’s free SEO checker, Site Audit, you can configure the tool to exclude parameterized URLs from crawling.
Open Site Audit, enter your domain, and click “Start Audit.”
In the setup wizard, select “URL parameter rules” and list the parameters you want to exclude from crawling. For example, entering “page” in the text box would exclude pagination parameters like “?page=1,” “?page=2, and “?page=3.”
After listing the parameters you want to ignore, click “Start audit.”
When the crawl is finished, Site Audit generates a report showing your site’s overall technical health.
You’ll also see a list of issues affecting your important content.
Review Site Audit’s findings and focus implementing fixes that are most likely to have the biggest impact. Generally speaking, prioritize errors first.
Use the Right Tools for Better URL Parameter Management
The below tools help you generate consistent campaign URLs, validate that your canonical tags are working as intended, and monitor for issues caused by parameterized pages:
- Google’s Campaign URL Builder lets you input campaign details to automatically create tracking URLs
- Google Search Console’s URL inspection tool lets you identify whether your intended canonical page is actually the Google has selected as the canonical version
- Site Audit highlights crawl inefficiencies and duplicate content issues that need to be addressed
