Utilising Robots.txt to Optimise Crawling Efficiency

Google recently reiterated the importance of using the robots.txt file to manage web crawlers effectively, particularly for blocking action URLs such as “add to cart” or “add to wishlist” links. This reminder is crucial for web administrators looking to optimise server resources and enhance user experience.

Understanding Robots.txt

The robots.txt file is a text document placed in the root directory of a website. It instructs search engine crawlers on which parts of the site they are allowed to crawl and index. This is particularly useful for preventing search engines from wasting resources on pages that don’t need to be indexed, such as action URLs that perform specific functions like adding products to a shopping cart.

Why Block Action URLs?

Action URLs often include parameters like ?add_to_cart or ?add_to_wishlist, which are not beneficial for search engine indexing. Allowing crawlers to access these URLs can lead to unnecessary server load and potential performance issues. For instance, a crawler might repeatedly trigger these actions, wasting bandwidth and processing power without any SEO benefit.

Best Practices for Using Robots.txt

To prevent such inefficiencies, it’s essential to configure your robots.txt file correctly. Here’s how you can do it:

Identify Action URLs: Determine the specific URLs or URL patterns that should be blocked. Common action URLs include those with parameters like?add_to_cart, ?add_to_wishlist, and similar.

Create Robots.txt Rules: Add rules to your robots.txt file to disallow crawlers from accessing these URLs. For example:

					User-agent: *
Disallow: /*?add_to_cart
Disallow: /*?add_to_wishlist

This code instructs all web crawlers (User-agent: *) to avoid any URLs containing the specified parameters.

Test Your Configuration: Use tools like Google Search Console to test your robots.txt file and ensure that the rules are correctly implemented. This helps in verifying that the blocked URLs are not being crawled.

Additional Tips

  • Avoid Overblocking: Be careful not to block essential pages that should be indexed. Ensure that your disallow rules are specific enough to target only the unwanted URLs.
  • Use HTTP Methods Wisely: While HTTP POST requests can prevent some crawler activities, remember that crawlers can still perform POST requests. Thus, robots.txt remains a more reliable method for controlling crawler behaviour.

Benefits of Proper Robots.txt Implementation

  1. Reduced Server Load: By preventing unnecessary crawler hits on action URLs, server resources can be better utilised for actual user traffic.
  2. Improved Crawling Efficiency: Search engines can focus on indexing relevant content, enhancing your website’s overall SEO performance.
  3. Enhanced User Experience: With optimised server performance, users will experience faster load times and smoother interactions.


Incorporating a well-configured robots.txt file is a simple yet effective way to manage web crawlers, reduce server load, and improve the overall efficiency of your website. By blocking action URLs, you ensure that your site operates smoothly and that search engines focus on indexing valuable content. This practice, although longstanding, remains vital in today’s digital landscape.