Robots.Txt Files and SEO - Best Practices and Solutions to Common Problems


Technical SEO is a well-executed strategy that takes into account various on-page and off-page ranking signals so that your website ranks better in the SERPs. Any SEO tactic will help improve your page rank by ensuring that web crawlers can easily crawl, rank, and index your site. 


From page speed to the right title tags, there are many ranking signals that technical SEO can help with. But did you know that one of the most important files for your website's SEO can also be found on your server?


The robots.txt file is a code that tells web crawlers which pages of your site they are allowed to crawl and which they are not allowed to crawl. This doesn't seem like a big deal, but if your robots.txt file isn't configured properly, it can have a serious negative impact on your site's search engine optimization.


In this blog post, you'll learn everything you need to know about robots.txt, from the importance of a robots.txt file for search engine optimization to best practices and the right approach to fixing common problems.


What is a robots.txt file and why is it important for SEO?

The robots.txt file is a file on your server that tells web crawlers which pages they can and cannot access. When a web crawler tries to crawl a page that is locked in the robots.txt file, it is considered a soft 404 error.


Although a soft 404 error won't hurt your site's ranking, it's still considered an error. And too many errors on your site can lead to a slower crawl rate, which can eventually affect your ranking due to the reduced crawling.


If your site has a lot of pages blocked by the robots.txt file, it can also lead to a waste of crawl budget. The crawl budget is the number of pages Google crawls each time you visit your site.


Another reason why robots.txt files are important for search engine optimization is that they give you more control over the way Googlebot crawls and indexes your site. If you have a website with many pages, you may want to exclude certain pages from indexing so that they don't overwhelm search engine web crawlers and affect your ranking.


If you have a blog with hundreds of posts, you should only allow Google to index your latest articles. If you have an eCommerce website with many product pages, you should only allow Google to index your most important category pages.


Properly configuring your robots.txt file can help you control the way Googlebot crawls and indexes your site, which can ultimately help improve your ranking.


What Google says about best practices in robots.txt files


Now that we've explained why robots.txt files are important for SEO, let's discuss some google-recommended best practices.


Create a file named robots.txt

The first step is to create a file called robots.txt. This file must be placed in the root directory of your website - the top-level directory that contains all the other files and directories on your website.


Here is an example of the correct placement of a robots.txt file: On the website apple.com, the root directory would be apple.com/.


You can create a robots.txt file with any text editor, but many CMS like WordPress automatically create it for you.


Add rules to the robots.txt file


After you create the robots.txt file, the next step is to add rules. These rules tell web crawlers which pages they can and cannot access.


There are two types of robot.txt syntaxes that you can add: Allow and Do Not Allow.


Allow rules tell web crawlers to crawl a specific page.


Disallow rules tell web crawlers not to crawl a particular page.


For example, if you want to allow web crawlers to crawl your homepage, you would add the following rule: 


Allow: /

If you want to prevent web crawlers from browsing a specific subdomain or subfolder on your blog, use:Disallow: /


Upload the robots.txt file to your website

After you add the rules to your robots.txt file, the next step is to upload them to your website. You can do this using an FTP client or your hosting control panel.


If you are not sure how to upload the file, contact your web host who can certainly help you.


Test your robots.txt file

After you upload the robots.txt file to your website, you need to test it to make sure it works correctly. Google provides a free tool called robots.txt Tester in Google Search Console that you can use to test your file. It can only be used for robots.txt files that are located in the root directory of your website.


To use the robots.txt tester, enter your website's URL into the robots.txt tester tool, and then test it. Google will then show you the contents of your robots.txt file as well as any errors found.


Use Google's open source robot library

If you're an experienced developer, Google also offers an open source robots library that allows you to manage your robots.txt file locally on your computer.


What can happen to your website's SEO if a robots.txt file is corrupted or missing?

If your robots.txt file is corrupted or missing, it can cause search engine crawlers to index pages that you don't want. This can eventually lead to these pages being ranked in Google, which is not ideal. It can also cause overloading of the site as the crawlers try to index everything on your site.


A broken or missing robots.txt file can also cause search engine crawlers to overlook important pages on your site. If you have a page that you want to index but is blocked by a broken or missing robots.txt file, it may never be indexed.


In short, make sure that your robots.txt file is working correctly and that it is in the root directory of your website. To resolve this issue, create new rules or upload the file to your root directory if it is missing.


Best Practices for robots.txt files

Now that you know the basics of robots.txt files, let's discuss some best practices. These are things you should do to make sure your file is effective and working properly.


Use a new row for each policy

When adding rules to your robots.txt file, it's important to use a new line for each policy so as not to confuse search engine crawlers. This applies to both the Allow and Do Not Allow rules.


For example, if you want to prevent web crawlers from crawling your blog and contact page, you would add the following rules:

Do not allow: /blog/

Do not allow: /Contact/

Using wildcards to simplify statements

If you want to block many pages, it can be time-consuming to add a rule for each page. Fortunately, you can use wildcards to simplify your instructions.


A wildcard is a character that can represent one or more characters. The most common placeholder is the asterisk (*).


For example, if you want to block all files with the extension .jpg, you would add the following rule:


Do not allow: /*.jpg


Use $to specify the end of a URL


The dollar sign ($) is another wildcard that you can use to specify the end of a URL. This is useful if you want to block a specific page, but not the pages that follow it.


For example, if you want to block the contact page but not the contact success page, you would add the following rule:


Do not allow: /Contact$


Use each user agent only once

Luckily, if you add rules to your robots.txt file, Google doesn't mind if you use the same user agent multiple times. However, it is considered best practice to use each user agent only once.


Use specificity to avoid unintentional errors

When it comes to robots.txt files, specificity is key. The more precisely you formulate your rules, the less likely you are to make a mistake that could harm your website's search engine optimization.


Use comments to explain your robots.txt file to people


Although your robots.txt files are crawled by bots, humans need to be able to understand, maintain, and manage them. This is especially true if several people are working on your website.


You can add comments to your robots.txt file to explain what certain rules do. Comments must be on their own line and start with a #.


For example, if you want to block all files with the extension .jpg, you can add the following comment:


Do not allow: /*.jpg # Blocks all files ending in .jpg

This would help anyone who needs to manage your robots.txt file to understand what the rule is for and why it is there.


Use a separate robots.txt file for each subdomain

If you have a website with multiple subdomains, it's best to create a separate robots.txt file for each. This helps organize things and makes it easier for search engine crawlers to understand your rules.


Common errors in robots file.txt and how to fix them

Understanding the most common mistakes people make with their robots.txt files can help you avoid them. Here are some of the most common mistakes and how to fix these technical SEO issues.


Missing robots.txt file

The most common error with robots.txt files is that they do not exist at all. If you don't have a robots.txt file, search engine crawlers assume that they are allowed to crawl your entire site.


To fix this, you need to create a robots.txt file and add it to the root directory of your website.


Robots.txt file not in the directory


If you don't have a robots.txt file in the root directory of your site, search engine crawlers won't be able to find it. As a result, they assume that they are allowed to crawl your entire site.


It should be a single text file name that should be placed in the root directory rather than in subfolders.


No sitemap URL

Your robots.txt file should always contain a link to the sitemap of your website. This helps search engine crawlers find and index your pages.


Omitting the sitemap URL in the robots.txt file is a common mistake that while it doesn't hurt your site's search engine optimization, adding the URL improves it.


Block CSS and JS

According to John Mueller, you should avoid blocking CSS and JS files, as Google search crawlers need them to render the page correctly.


Of course, if the bots can't display your pages, they won't be indexed either.


Using NoIndex in robots.txt

As of 2019, the noindex robots meta tag is deprecated and is no longer supported by Google. As a result, you should no longer use it in your robots.txt file.


If you are still using the noindex robots meta tag, you should remove it from your website as soon as possible.


Improper use of placeholders

Incorrect use of wildcards will only restrict access to files and directories that you did not intend.


Be as specific as possible when using wildcards. This will help you avoid mistakes that could harm your website's search engine optimization. Also, stick to the supported wildcards, i.e. asterisks and dollar signs.


Incorrect file type extension

As the name suggests, a robot.txt file must be a text file that ends in .txt. It cannot be an HTML file, an image, or any other type of file. It must be created in UTF-8 format. A useful introductory resource is Google's robot.txt guide and the Google Robots .txt FAQ.

Using Robot.Txt files like a profile


A robots.txt file is a powerful tool that you can use to improve your website's search engine optimization. However, it is important to use them correctly.


Used correctly, a robots.txt file can help you control which pages are indexed by search engines and improve the crawlability of your site. It can also help you avoid problems with duplicate content.


On the other hand, a robots.txt file can do more harm than good if used improperly. It's important to avoid common mistakes and follow the best practices that will help you realize the full potential of your robots.txt file and improve your website's SEO. In addition to expert navigation in robots.txt files, dynamic rendering with Prerender also provides the ability to generate static HTML for complex JavaScript websites. Now you can enable faster indexing, faster response times, and an overall better user experience.