How Is the Robots.txt File Used for SEO?

The robots.txt file is an important part of search engine optimization (SEO) that can help improve your web pages’ visibility in search engines. This article will describe what the robots.txt file is, how it works and how you can use it to improve your site’s SEO. We’ll also look at some best practices and tips for making the most of this powerful tool.

What Is Robots.txt?

Robots.txt is a text file that tells bots, including search engine crawlers, which pages and files on a website they should be able to see and index. Its main job in SEO is to instruct search engine crawlers like Googlebot not to look at certain pages. 

For example, you might want to tell them not to look at the category pages of your blog or online store because you don’t want those pages in search results. Other uses include preventing the indexing of duplicate content and other files you may not want indexed, including scripts and images.

Robots.txt can help ensure that your site’s crawl budget is used efficiently. Search engines tend to limit the number of pages they crawl each day. Site owners often want to focus their crawl budget on specific pages, and the robots.txt file can be used to ask Google not to use it on less important pages.

Does Robots.txt Stop Bots from Indexing Pages?

Well-behaved bots follow the directives in your robots.txt file. However, not all bots are well-behaved, and those that aren’t crawl whatever they like. Fortunately, Google and other major search engines usually obey robots.txt instructions.

But even if you use your robots.txt file to stop crawling, Google will still be able to see the pages via external links, so they may end up in search engine results anyway. If you want pages to be on the web but invisible, Google suggests password-protecting them. 

You can also use the noindex tag to prevent indexing. But don’t use robots.txt and noindex together to block pages—if Google can’t crawl a page because it is blocked in robots.txt, it can’t see the noindex directive and therefore may index the page and show it in search results. 

Useful Robots.txt Directives for SEO

Here are four robots.txt directives you may find useful for search engine optimization:

  1. User-agent: * – Directives are divided into blocks, each of which begins with a user-agent line indicating which user-agent (crawlers, browsers, and so on) it applies to. The asterisk (*) indicates all user-agents, but you can name specific agents like “Googlebot.”
  2. Disallow: /cgi-bin/ – This directive prevents search engine bots from crawling and indexing the files in the cgi-bin folder. 
  3. Allow: /images/ – This directive tells search engine bots that they are allowed to crawl and index the files within the images folder. Allow directives are used to override disallow directives. For example, you may want to allow access to a folder inside a disallowed parent folder. 
  4. Sitemap: – This directive specifies which sitemap should be used, helping bots discover new content faster and more accurately.

In a robots.txt file, these directives would look like the following:

User-agent: *

Disallow: /cgi-bin/

Allow: /images/


Make Sure Your Robots.txt File Is Error-free

A word of warning: Make sure your robots.txt directives precisely follow the specification. Mistakes result in unexpected behavior that could hurt your site’s SEO. To be sure, run your robots.txt file through a validator.

Author: Terry Cane

Terry Cane is a technical writer for, a reliable and supportive SEO hosting partner.