Robots.txt is a text file located in the root directory of a web server that provides instructions to “web robots” such as web crawlers and search engine bots. The concept of robots.txt was introduced by the Robots Exclusion Protocol (REP) in the early 1990s with the purpose of controlling which parts of a website these robots could access and index (source: Internet Engineering Task Force, 1994).
A single line in a robots.txt file may look like “Disallow: /private/” which tells web robots not to access any URLs that start with “/private/”. This is important because it allows webmasters to hide sensitive information or to prevent overloading of their servers due to frequent crawling.
For example, the robots.txt file for Google.com contains instructions that prevent web crawlers from accessing the “ads” and “search” directories, by using lines like “Disallow: /ads/” and “Disallow: /search”(source: google.com/robots.txt).
However, it is important to note that robots.txt is simply a directive, and it is up to the bot to comply with the instructions listed. Good bots, like those of major search engines such as Google and Bing, are programmed to respect the rules in this file. Bad bots, however, including certain malware bots, email harvesters, and spam bots, do not (source: Google Search Central, 2021).
Another noteworthy feature is the use of the “User-agent” directive. This directive allows the rules in the robots.txt file to be tailored for specific bots. A webmaster might want one bot to crawl a part of the site, but not another. For example, a line like “User-agent: Googlebot” would apply only to Google’s web crawler (source: Google Search Central, 2021).
Unintentional misconfiguration of the robots.txt file can have severe implications such as accidental blocking of whole websites from search engines, leading to decreases in organic traffic. Therefore, precise management of the robots.txt file is critical (source: Yoast SEO, 2021).
To summarize, robots.txt is a powerful tool that is used to give directions to web robots about which parts of a website to access and index. It plays an instrumental role in optimizing the way that search engines interact with websites, contributing significantly to a site’s SEO strategy.
Sources:
1- Internet Engineering Task Force, 1994. [Link]
2-Google Search Central, 2021. [Link]
3- Google’s robots.txt file [Link]
4- Yoast SEO, 2021. [Link]
