What Is a Robots.txt File and Why Is It Important?

Learn how robots.txt files play a crucial role in directing crawler bots to the correct web pages, optimizing search engine rankings, and discover the types of robots.txt files, common issues, and more.
Last Updated November 1, 2023
What is Robots.txt?

Robots.txt is a text file and piece of code that tells crawlers how to move through a website. It’s a directive, which means it guides crawler bots to the right web pages. Essentially, it tells search engines which pages to crawl.

If you’ve ever driven along a new route without a GPS, you know the importance of road signs. As you’re driving, these signs tell you where you need to turn, which exits you need to take, and which lanes you need to be in to get where you’re trying to go. Without those signs, you’d have a high chance of going the wrong way.

Well, guess what? Google needs road signs, too. Not for driving down the road, though — for crawling your site. Sure, it could just go wild with its crawling, but that wouldn’t be great for your search engine optimization (SEO). No — you want Google to crawl specific pages in specific ways. For that, you need to give those crawlers directions.

Robots.txt files are how you do that. But what in the world are robots.txt files, and how do they impact your SEO? On this page, we’ll cover:

Keep reading to learn more about using robots.txt for SEO!

What is a robots.txt?

Robots.txt is a text file and piece of code that tells crawlers how to move through a website. It’s a directive, which means it guides crawler bots to the right web pages. Essentially, it tells search engines which pages to crawl.

How robots.txt impacts SEO

The main thing that robots.txt files do is tell Google which pages to crawl and which ones not to crawl — though it doesn’t totally control what Google does. These directives are suggestions, not commands. To forcibly prevent Google from crawling a page, you’d need noindex meta directives, not just robots.txt files.

At first glance, it might seem like you want all the pages on your website to be ranking in search results. That’s maximum SEO, right?

Well, not exactly. For a lot of pages on your site, that’s true. But there are probably some pages you don’t want ranking as well. For example, let’s say someone makes a purchase in your online store, and they’re then greeted by a page that says, “Thank you for your purchase.”

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“Google only indexes images and videos that Googlebot is allowed to crawl.”

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Now imagine someone searching for your business in search results and finding that page. It would make no sense for a “Thank you for your purchase” page to appear in search results to people who’ve made no such purchase. That’s one page you don’t want ranking.

Odds are, you have a few pages on your site that that’s the case for. The same goes for login pages and duplicate pages. Robots.txt prevents Google from ranking those pages and focuses on crawling pages you want to appear in search, like blog posts and service pages.

When should you update a robots.txt file?

Even after you create a robots.txt file, you’ll likely need to update it at some point. But when might you need to do that, exactly?

Here are a few times when you might update your robots.txt file:

  • When you migrate to a new content management system (CMS)
  • When you want to improve how Google crawls your site
  • When you add a new section or subdomain to your site
  • When you change to a new website altogether

All of these changes require you to go in and edit your robots.txt file to reflect what’s happening on your site.

Common issues with robots.txt files

Sometimes, websites experience issues when using robots.txt. One potential problem is that the file blocks Google (or other search engines) from crawling your website at all. If you find that something like that is happening, you’ll want to update your robots.txt file to fix that.

Another potential issue is that there’s sensitive or private data somewhere on your site (private either to your business or to your customers), and the robots.txt file doesn’t block it, allowing Google to freely crawl that data. That’s a huge breach, so you need to make sure you block that data from crawlers.

5 examples of robots.txt files

There are a few different types of robots.txt files that you can use. Let’s go through a few of those types below:

Allow all

One example of a robots.txt file is a “Allow all” directory. This type of file indicates that any and all bots are allowed to crawl your website. The “Allow all” command looks like this:

User-agent: *


Disallow all

The “Disallow all” command is the exact opposite of the “Allow all” command. It basically says that no bots of any kind are allowed to crawl your site, blocking it off altogether. This command looks almost identical to the “Allow all” command, with the only difference being the addition of a slash:

User-agent: *

Disallow: /

Disallow a bot

Sometimes you don’t want to block all bots from crawling your site — just certain ones. In that case, you can use the command to disallow a specific bot. This command looks like this:

User-agent: Twitterbot

Disallow: /


User-agent: *


In the above example, we’ve blocked Twitterbot from crawling the website. However, you can do this for whichever bot you want.

Block a folder

It’s not always a question of blocking bots. Sometimes you’re fine with any bot crawling your site, you just don’t want them to be able to access certain folders. In that case, you can use this command to block a particular folder from being accessed:

User-agent: *

Disallow: /admin/

In this example, we’ve blocked the admin portion of the site. That’s one of the most common areas for site owners to block from crawlers. However, you could replace the word “admin” with a different portion of your site if there’s another folder you wanted to block.

Block a file

Finally, you might want to block a specific file instead of a whole folder. In that case, you would use the following command format:

User-agent: *

Disallow: /demo23.html

In this example, the command is blocking a file called “demo23.html.” But you would replace that with whichever specific file you were trying to block off.

Learn more SEO tips and tricks on SEO.com

If you want to learn more about using robots.txt for SEO — along with tons of other useful SEO tactics — you’re already in the right place. Be sure to check out some other helpful articles right here on SEO.com or reach out to one of our strategists about our technical SEO services that can help you optimize your robots.txt file for peak SEO performance.

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