Using Robots.txt in SEO: Complete Guide to Robots.txt File

Robots.txt in SEO

Search engine optimization (SEO) is crucial for driving organic traffic to your website. One important but often overlooked aspect of technical SEO is configuring your robots.txt file properly.

The robots.txt file tells search engine crawlers which pages or directories to avoid indexing on your site. It allows you to hide pages you don’t want to be indexed, like internal administration pages or pages with duplicate content. Having a well-structured robots.txt file can help your SEO strategy.

In this complete guide, we’ll cover everything you need to know about using robots.txt for SEO, including:

What is a Robots.txt File?

A robots.txt file is a simple text file that gives instructions to search engine robots crawling your site. It tells these automated bots which directories or pages they should avoid when indexing your site.

The robots.txt file uses the Robots Exclusion Protocol, which is an informal standard that search engine crawlers understand. When a robot visits your site, it will first check for a robots.txt file and read the instructions before crawling.

How Does Robots.txt Work?

When a search engine crawler visits your site, it will look for a robots.txt file in the root directory. Here is the basic workflow:

  1. The search engine robot arrives at your homepage URL (e.g. https://www.example.com).
  2. It first checks for a robots.txt file in the root folder (https://www.example.com/robots.txt).
  3. The robot reads the instructions in your robots.txt file.
  4. It crawls and indexes pages on your site while avoiding any URLs you have disallowed.

If no robots.txt file exists, the crawler will index all discoverable pages on your site.

Robots.txt Syntax and Directives

The robots.txt file uses a simple syntax with two main directives:

User-agent

This specifies which search engine bots should follow the rules. Common user-agents include:

  • Googlebot (for Google search)
  • bingbot (for Bing search)
  • (wildcard applies to all bots)

Disallow

This tells bots which URLs they should not crawl or index. Some examples:

Disallow: /private/

Disallow: /tmp/

Disallow: /category/books/

Any URL path typed after “Disallow:” will be blocked for that bot.

Here is an example robots.txt file:

User-agent: Googlebot

Disallow: /private/

User-agent: *

Disallow: /tmp/

This file blocks the /private/ path for Googlebot and the /tmp/ path for all bots crawling the site.

Best Practices for Robots.txt

When creating or updating your robots.txt file, keep these best practices in mind:

  • Be selective – Avoid blanket disallowing entire directories or site sections unless absolutely necessary. Overblocking can hurt your indexation and rankings.
  • Keep it simple – The robots.txt file should be easy to interpret at a glance. Avoid overly complex conditional logic.
  • Test thoroughly – Use a robots.txt testing tool to validate that your directives are working as intended. Monitor search engine indexes regularly.
  • Don’t block site maps – Allow your XML sitemaps to be crawled so search engines can discover new URLs.
  • Place internal first – List “disallow” rules meant for internal use at the top since public bots tend to ignore subsequent directives.
  • Use crawling directives – Optional directives like “Crawl-delay:” allow you to slow (but not block) crawling of certain paths.
  • Combine with meta robots – Use meta robots “noindex” tags on individual pages as a complementary strategy to robots.txt blocking.
  • Set proper precedents – Order directives properly so more specific user-agents take precedence over general ones in case of conflict.

When to Use Robots.txt for SEO

There are a few common cases where implementing robots.txt directives can help your SEO strategy:

Blocking Duplicate Content

Prevent the crawling of print pages, stagnant directories, or other areas on your site that contain duplicate content. This helps avoid search engine penalties.

Hiding Confidential Data

Block pages that contain private user info, sensitive documents, or other internal data you don’t want to be indexed publicly.

Speeding Up Crawling

Identify resource-heavy sections of your site and use crawling delays or visit rate limits in robots.txt to ease the load on your servers.

Removing Old Content

If you have a site rebuild or content overhaul, use robots.txt to block search engines from indexing outdated on-site content that remains available but should not be crawled.

Preventing Media Indexing

For multimedia-heavy sites, block resource-draining file types like .mp3, .wmv, or image directories from being crawled.

In most cases, you want search engines to crawl and index your important content pages. Strategic blocking with robots.txt should only be used where you see a clear SEO need.

Robots.txt File Examples

Here are some examples of common robots.txt files and directives:

Block an Entire Directory

User-agent: *

Disallow: /tmp/

This completely blocks the /tmp/ directory from all search engine bots.

Block Specific File Types

User-agent: *

Disallow: /*.pdf$

Disallow: /*.docx$

This blocks all PDF and Word documents from being indexed while allowing other content to be crawled.

Block and Slow Down Bots

User-agent: *

Disallow: /thank-you-pages/

User-agent: Googlebot

Crawl-delay: 10

These rules block all bots from a duplicate content directory while slowing down Googlebot to decrease the crawling load.

Allow Bots to Index Only Homepage

User-agent: *

Disallow: /

User-agent: Googlebot

Allow: /

This approach allows Googlebot to index only the homepage, blocking everything else. Generally not recommended.

The optimal robots.txt file will be specific to your site architecture and SEO goals. Test directives carefully before deploying site-wide.

Tools for Checking Robots.txt

Testing your robots.txt file is crucial before rolling out changes. Here are some useful tools:

  • Google Search Console – Provides reports on indexed vs blocked URLs and validates robots.txt directives.
  • Bing Webmaster Tools – Like Search Console, it gives robots.txt insights specific to Bingbot.
  • Screaming Frog – SEO crawler that has a robots.txt tester in the configuration tab.
  • Botify – Paid SEO platform with an integrated robots.txt analyzer.
  • Turing Robot – Free tool that lets you validate a robots.txt file by URL or by directly inputting the directives.
  • Robotstxt.org – Simple online parser that shows you which URLs would be allowed vs disallowed for major bots.

Test your robots.txt file before and after making updates to avoid accidentally blocking important pages from search engine indexing. Monitor indexation regularly in search engine webmaster tools.

Common Robots.txt Mistakes

It’s easy to make robots.txt mistakes that inadvertently block search engine bots. Some common errors include:

  • Blocking all bots – Overly strict directives like “Disallow: /” that prevent all crawling. Hurts SEO visibility.
  • Blocking site maps – Disallowing the XML sitemap file location, blocking important new URLs from being discovered.
  • Too many directives – Unnecessary complexity that makes the file hard to parse and maintain long-term.
  • Incorrect syntax – Simple typos, wrong order of directives, invalid formatting. Causes unpredictable bot behavior.
  • Not testing thoroughly – Not validating with tools or monitoring indexing impact before and after robots.txt changes.
  • Forgetting about mobile – Blocking directives for desktop bots but allowing poor-quality mobile URLs to be indexed.

Avoid these mistakes by keeping your robots.txt file streamlined, testing it continuously, and checking search engine data often to validate that your directives are working as you expect.

Optimizing Robots.txt for E-commerce Sites

E-commerce sites have some unique considerations when it comes to robots.txt configuration:

  • Allow product category and product pages to be indexed – These are critical landing pages.
  • Block order tracking pages – These contain private customer data and don’t need indexing.
  • Use “noindex” tags on cart/checkout pages – Prevents indexing without blocking bots entirely.
  • Allow site maps and RSS feeds – Helps surface new product pages.
  • Delay crawling on high-traffic pages – Prevents overload on servers and APIs.
  • Block paid search landing pages – Avoid indexing unnecessary parameter-heavy URLs.
  • Disallow low-value categories – For example, exclude brand directories or empty content categories.
  • Consider SEO value before blocking – Don’t default to blocking pages, only where you see clear benefits.

As with any site, test e-commerce robots.txt directives in a staging environment first. Crawl your site to identify duplicate, thin, or over-optimized pages to consider blocking.

Robots.txt as Part of a Larger SEO Strategy

While an optimized robots.txt file can provide SEO benefits, it is just one technical component of a comprehensive strategy.

To maximize search visibility, you still need:

  • Quality content – Well-written, informative pages targeting your core keywords.
  • Fast site speed – Quick page load times optimize crawling and user experience.
  • Mobile responsiveness – A site designed for any device with structured data and AMP pages.
  • Effective linking – An internal link structure that facilitates discovery and good flow.
  • Strong metadata – Page titles, descriptions, headings, and image alt text.
  • Monitoring tools – Like Search Console and analytics to track keyword rankings and traffic.

Robots.txt should not be used to try to manipulate your way into better indexing. Focus on providing search engines and users with the best possible experience.

Conclusion

A clean, well-structured robots.txt file is a foundational element for any SEO strategy. It allows you to manage crawler access to optimize indexing.

Be selective with blocking directives, use them only where you see clear benefits. Avoid over-blocking content, and be sure to test your directives thoroughly.

Use robots.txt as one piece of a comprehensive approach to onsite and technical SEO. By making your site as crawler-friendly as possible, you will maximize discoverability and organic search visibility over the long term.

Contact 427 Digital to help you manage Robots.txt file and save your crawling budget on essential pages!