Introduction
When search engines like Google, Bing, and Yahoo visit any website, they use automatic bots (also known as a crawler) to scan and index website’s content. But what if you do not want some pages or files to be accessed by these bots? This is the place where robots.txt file comes in.
In this guide, we will start with the basic things and gradually dive into advanced techniques and help you to understand and use robots.txt to control the search engine crawling and use it effectively.
Table of Contents
What is Robots.txt?
Robots.txt file is a small text file placed in the root directory of a website. It provides instructions to search engine crawlers about which parts of the site have been allowed or not allowed to access. Think of it as a “road sign” for search engines that tell them where and cannot go
Why is Robots.txt Important?
- Controls Search Engine Crawling – robots.txt helps to manage which parts of your website should be indexed and which should be not.
- Improves Crawl Budget – robots.txt prevents bots from wasting resources on unnecessary or restricted pages.
- Protects Sensitive Data – robots.txt prevents crawlers from accessing admin pages or confidential content.
- Prevents Duplicate Content Issues – Helps avoid indexing similar pages that can damage the SEO rankings.
Where is Robots.txt Located?
This file is always placed in the root folder of your website. You can check the robot .txt file of any site by visiting:
https://www.example.com/robots.txt
How Robots.txt Works
When a search engine bot arrives at any website, it first looks for the robots.txt file. This file contains instructions that guide the bot on what it can and cannot crawl.
A simple robots.txt file may look like this:
User-agent: *
Disallow: /admin/
Disallow: /private/
Understanding the Syntax:
- User-agent: it defines on which bot the rule applies to (* means all bots).
- Disallow: Prevents specific pages or directories from crawling.
- Allow: (Used mainly for Googlebot) Allows specific pages within blocked sections.
- Sitemap: Tells the search engines where to find a website’s XML sitemap.
Example of allowing Googlebot to crawl a specific page inside a blocked folder:
User-agent: Googlebot
Disallow: /private/
Allow: /private/allowed-page.html
Best Practices for Robots.txt
1. Block Unnecessary Pages
You can prevent search engines from crawling pages that don’t need to appear in search results.
User-agent: *
Disallow: /cart/
Disallow: /checkout/
2. Block Specific Bots
If you want to prevent certain bots from crawling your site, specify their names.
User-agent: BadBot
Disallow: /
3. Prevent Indexing of Duplicate Content
Avoid indexing filters and category pages that may create duplicate content.
User-agent: *
Disallow: /category/page/
4. Add Your Sitemap for Better Indexing
Sitemap: https://www.yourwebsite.com/sitemap.xml
Advanced Robots.txt Techniques
Using Wildcards for Flexible Rules
To block multiple pages with similar patterns:
User-agent: *
Disallow: /private*/
Disallow: /*.pdf$
- * matches any sequence of characters.
- $ ensures that only URLs ending with .pdf are blocked.
Blocking Parameterized URLs
Stop crawlers from indexing dynamically generated pages:
User-agent: *
Disallow: /*?sessionid=
Blocking Image Indexing
Prevent Google Images from indexing pictures on your site:
User-agent: Googlebot-Image
Disallow: /
Blocking All Crawlers (Not Recommended for SEO)
User-agent: *
Disallow: /
Common Mistakes to Avoid
- Accidentally Blocking Important Pages – Before making it live, please ensure that you don’t block your homepage, blog content or any important pages.
- Using Robots.txt for Security – This file can be seen publicly, so don’t use it to hide any sensitive data. In that case you can use alternative techniques.
- Blocking CSS & JavaScript Files – This can impact search engines’ ability to render your site properly.
- Forgetting to Test Your Rules – Always check your robots.txt settings using SEO tools, Search console or manually.
How to Test Your Robots.txt File
To make sure your robots.txt file is working correctly, use:
- Google Search Console Robots.txt Tester: https://search.google.com/search-console
- SEO Tools: Screaming Frog, Ahrefs, SEMrush provide robots.txt validation.
Conclusion
Robots.txt file is a simple but powerful tool to control how to crawl your website by Search Engines. By using it carefully, you can improve site efficiency, manage the crawl budget, and prevent indexing of unnecessary pages or files. However, wrong use can damage your SEO performance, so always test and monitor your robot.txt settings. If you are uncertain about optimizing your robots.txt file, reach out for expert SEO guidance today!