robots.txt acts as the gatekeeper for webmasters. What are its uses, and how does it assist in SEO? This article will explain in detail.
I mentioned before in Building a Website with SEO Ranking Capabilities where I said robot.txt do not directly impact SEO, you can also check it out too.
What is robots.txt? What impact does it have on crawlers and visitors?
robots.txt is a plain text file that can be opened with a text editor and is typically placed in the root directory. According to Google’s official explanation, this file informs search engine crawlers which URLs on the website can be accessed.
Simply put, it is a protocol letter from the website operator to the crawler, primarily informing the crawler about specific web pages that it does not wish to be fetched. If you issue a command to prevent a page from being crawled, visitors can still open the page normally, so there is no impact on visitors. Additionally, this protocol “prevents the honest but not the dishonest,” thus only compliant crawlers like Google’s googlebot will refrain from fetching your pages.
Four Essential Uses of robots.txt for Website Operation
Since we cannot completely prevent crawlers from accessing our pages, why is it still necessary to establish a robots.txt? For webmasters focused on SEO, robots.txt serves the following purposes:
Control the content that you want to be indexed by search engines
As mentioned, we can use this file to set disallow rules to prevent search engines from indexing certain specific pages.
Save crawling budget
Search engines have a certain quota on how often and how many pages they crawl each visit. By blocking less important pages, we can increase the efficiency of indexing important pages.
Avoid duplicate content
In addition to allowing priority pages to be fetched, we can block duplicate content. There are many ways to handle duplicate content, and robots.txt is one of the means to implement this.
Submit XML Sitemap
Lastly, we can place the path to our XML Sitemap in this file, informing search engines where our Sitemap is located.
Practical Recommendations for Using robots.txt to Block Pages
Generally, our reasons for blocking pages stem from the above purposes. Practically, we recommend not allowing the following types of pages to be crawled by Google:
Search result pages: These can create duplicate content.
Program files: Generally ineffective for SEO, these are recommended to be blocked to save the crawling budget. Additionally, some comment files also generate pages, such as websites setting up comment functions for products, which can lead to duplicate content if not always commented on.
Shopping checkout pages, password-protected pages, and member pages: Pages that do not need to be searched.
Advertising and campaign landing pages: Can block short-term advertising pages.
Print-friendly pages: Pages created to make print layouts look better, which are now rare.
Dynamic pages that are not needed for indexing and can cause duplicate content: Some pages are necessary, but upon our evaluation, still need to be blocked, such as pages that generate very similar content but have different URL parameters.
Understanding robots.txt Syntax and Regulations
The content of a robots.txt file is straightforward and mainly includes the following syntax:
User-agent: The name of the crawler; if User-agent is * (wildcard), it means all crawlers.
Disallow: URLs not allowed to be crawled.
Allow: URLs allowed to be crawled.
Tip: You can use robots.txt testing tools to check which pages your robots.txt is blocking.
Important Notes on robots.txt
- The file size must not exceed 500 KB.
- Google specifically instructs not to block JavaScript / CSS / Images.
- Subdomains are essentially different websites, so remember to set up a robots.txt file for each.
- Google SEO does not require using crawl-delay to reduce indexing frequency, as Google no longer considers it.
Conclusion
robots.txt serves as a vital tool for website administrators by guiding search engine crawlers about which parts of the site should or should not be accessed. This not only helps in controlling the content that gets indexed but also plays a significant role in managing the site’s crawling budget, avoiding duplicate content, and effectively directing search engines towards the site’s XML Sitemap.
While robots.txt cannot completely prevent all crawlers from accessing all pages—particularly those that do not adhere to the rules—it provides a fundamental layer of control for SEO purposes. It’s important for webmasters to use robots.txt wisely to ensure their website’s content is indexed efficiently and accurately, maximizing SEO impact while safeguarding against unnecessary resource use.