robots.txt

What is a robots.txt File?
A robots.txt file is a simple text file that website owners place in the root directory of their website (e.g., www.example.com/robots.txt). This file provides instructions to web crawlers (also known as spiders or bots), such as Googlebot, about which parts of the website they should or should not crawl and index.
Think of it as a set of traffic rules for web crawlers. It doesn’t prevent access to your website for users, but it guides how search engines explore and index your content.
Standards & definition
The robots.txt protocol is defined in RFC9309 and is adhered to by most of the crawlers. You can also find
information on robotstxt.org.
List of bots
The list of bots currently available in dropdown is not exhaustive, you can always see crawlers rising everyday. To shut them all up just use * under bot (user-agent) input.
Here’s a list of bots known (again not an exhaustive list)
Key Points
  • Purpose:
    • Control Crawling: Determine which parts of your website search engines should crawl and index.
    • Protect Sensitive Data: Prevent sensitive information (like internal documents or login pages) from being indexed.
    • Improve Website Performance: Reduce the load on your server by limiting the number of pages crawled.
    • Optimize Crawl Budget: Guide crawlers to the most important pages on your site.
  • How it Works:
    • Crawlers start by checking for a robots.txt file at the root of your website.
    • If found, they read the instructions within the file.
    • Crawlers generally respect the instructions in robots.txt, though they may not always adhere to them completely.
  • Location:
    • The robots.txt file must be placed in the root directory of your website (e.g., www.example.com/robots.txt).
  • File Format:
    • It’s a plain text file using UTF-8 encoding.
In summary,
The robots.txt file is a fundamental aspect of website management. By understanding its purpose and how to use it effectively, you can control how search engines interact with your website, protect sensitive data, and improve your overall online presence.
How Crawlers Use robots.txt
Search engine crawlers, such as Googlebot, utilize the robots.txt file as a guide to navigate your website. When a crawler encounters a website, it first checks for the presence of a robots.txt file in the root directory. If found, the crawler meticulously analyzes the directives outlined within the file. These directives typically instruct the crawler on which parts of the website to crawl and index, and which areas to avoid.
Generally, crawlers strive to adhere to the instructions provided in the robots.txt file. However, it’s crucial to remember that adherence to these directives may not always be absolute. While robots.txt primarily serves as a guide for crawler behavior, it’s not an ironclad rule. Crawlers may occasionally deviate from the specified instructions.
robots.txt Syntax and Directives
The robots.txt file uses a simple syntax to define rules for web crawlers.
  • User-agent:
    • Specifies which crawlers the following directives apply to.
    • Example: User-agent: Googlebot
  • Disallow:
    • Prevents crawlers from accessing specific URLs or directories.
    • Example: Disallow: /admin/
  • Allow:
    • Allows access to specific URLs or directories, often used to override a previous Disallow directive.
    • Example: Allow: /images/
  • Sitemap:
    • Provides the URL of your sitemap file to help crawlers discover and index your website more efficiently.
    • Example: Sitemap: https://www.example.com/sitemap.xml
These directives work together to create a set of rules that control how crawlers interact with your website.
Note: The robots.txt file is case-insensitive, and comments can be added using the “#” symbol.
Common robots.txt Examples
Here are some common examples of robots.txt directives:
  • Block All Crawlers:
    User-agent: *
Disallow: /

    This directive blocks all crawlers from accessing any part of your website.
  • Allow All URLs:
    User-agent: *
Allow: /

    This directive allows all crawlers to access all parts of your website.
  • Disallow All URLs:
    User-agent: *
Disallow: /

    This directive blocks all crawlers from accessing any part of your website.
  • Allow Some URLs and Disallow Others:
    User-agent: *
Allow: /blog/
Allow: /contact/
Disallow: /admin/
Disallow: /members/

    This example allows crawlers to access the /blog/ and /contact/ directories while blocking access to the /admin/ and /members/ directories.
  • Using Regex for Specific File Types:
    User-agent: *
Allow: /*.png$ 
Disallow: /*.mp4$

    This example allows crawlers to access all PNG files while blocking access to all MP4 files.
These examples demonstrate some of the basic ways you can use robots.txt to control how crawlers interact with your website.
Frequently Asked Questions (FAQs)
  1. What happens if I don’t have a robots.txt file?
If you don’t have a robots.txt file, search engine crawlers will generally assume they have permission to crawl all pages on your website.
  1. Can I block users with robots.txt?
No, robots.txt only controls how search engine crawlers interact with your website. It does not block access for human users.
  1. Can I completely block a search engine from my website?
Yes, you can block a specific search engine by adding a User-agent directive followed by a Disallow: / directive for that specific search engine. However, it’s generally not recommended to block major search engines.
  1. How often should I update my robots.txt file?
You should update your robots.txt file whenever you make significant changes to your website’s structure or content, such as adding new sections, removing old pages, or changing the location of important files.
  1. Where can I test my robots.txt file?
You can use Google Search Console to test your robots.txt file and see how Googlebot views your website.
  1. Can I use robots.txt to improve my website’s SEO?
Yes, by using robots.txt effectively, you can guide crawlers to your most important pages, which can improve your website’s search engine rankings.
  1. Can I use wildcards in robots.txt directives?
Yes, you can use wildcards (such as ) to match multiple URLs or directories. For example, Disallow: /folder/ will block all files and directories within the /folder/ directory.
  1. What happens if I make a mistake in my robots.txt file?
If you make a mistake in your robots.txt file, it could prevent search engines from crawling and indexing important pages on your website, which could negatively impact your search engine rankings.