What is a Subdomain and How Does It Work?

June 4, 2024
What is a Subdomain and How Does It Work?

Navigating the digital landscape can be complex. One term you might have come across is "subdomain".

But what exactly is a subdomain? How does it work?

In this article, we'll delve into the world of subdomains. We'll explore their structure, uses, and how they impact your website's SEO.

Whether you're a website owner, a digital marketer, or just curious, this guide will provide a comprehensive understanding of subdomains. Let's get started.

Understanding Subdomains

A subdomain is a subset or a secondary part of a primary domain. It's a way to organize and navigate different sections of a website.

For instance, if you have a blog on your website, you might use a subdomain like "blog.example.com". Here, "blog" is the subdomain.

Subdomains are not just for blogs. They can be used for e-commerce stores, customer portals, localization, and more. They can also serve as testing environments or staging sites.

The Domain Name System (DNS) plays a crucial role here. It directs traffic to the correct subdomain.

In essence, subdomains offer a way to structure your website in a way that enhances user experience and site management.

Subdomain Structure Explained

The structure of a subdomain is quite simple. It's typically a prefix to the main domain.

For example, in the URL "blog.example.com", "blog" is the subdomain. "Example.com" is the main domain.

Diagram showing the structure of a subdomain

by Robby McCullough (https://unsplash.com/@mybbor)

The subdomain comes before the main domain in the URL. It's separated by a dot.

This structure allows for easy navigation. Users can directly access different sections of a website.

In conclusion, understanding the structure of a subdomains is key to using them effectively.

Subdomains vs. Subdirectories: SEO and Use Cases

Subdomains and subdirectories are both used to organize a website. However, they serve different purposes.

A subdirectory is part of the main domain. It's often used to organize content within the same website. For example, "example.com/blog" is a subdirectory.

On the other hand, a subdomain can function as a separate website. It can have its own branding and content. This makes subdomains ideal for large websites with distinct sections.

There's an ongoing debate about the SEO implications of subdomains and subdirectories. Some argue that subdirectories are better for SEO. They believe that search engines view a subdomain as a separate website. This could dilute the SEO value of the main domain.

Others argue that subdomains can be beneficial for SEO. They can target specific keywords and audiences. This can improve the relevancy of the content.

Here are some common use cases for subdomains:

  • E-commerce stores with different product lines
  • Blogs with distinct themes
  • Customer portals with unique interfaces
  • Localization for different regions or languages

In conclusion, the choice between a subdomain and a subdirectory depends on your website's needs and SEO strategy.

How to Create and Configure a Subdomain

Creating a subdomain is a straightforward process. It usually involves your hosting provider's control panel.

First, you need to log into your hosting account. Look for the "Subdomains" section. Here, you can add a new subdomain to your main domain.

After creating the subdomain, you need to configure it. This involves setting up DNS records. These records direct traffic to the correct subdomain.

Remember to secure your subdomain with an SSL certificate. This ensures that data transferred between the user and the subdomain is encrypted.

<A screenshot of a hosting provider's control panel>

by Luke Chesser (https://unsplash.com/@lukechesser)

Using a Caddyfile for Subdomain Configuration

Caddy is a web server that can be configured using a Caddyfile. It's a powerful tool for managing subdomains.

To configure a subdomain in a Caddyfile, you need to specify the subdomain name. Then, you define the root directory for the subdomain.

Remember to include the necessary directives for your subdomain. These directives control how Caddy handles requests for your subdomain.

Finally, test your Caddyfile configuration. Make sure that your subdomain is working as expected.

Transitioning from a Subdomain to a Main Website

There are times when you might want to move your website from a subdomain to the main domain. This could be due to SEO considerations or a change in your website's structure.

The process involves several steps. It's important to plan this transition carefully to avoid any disruption to your website's operation.

One key step is setting up redirects. This ensures that users and search engines can find your content after the move.

You also need to update your internal links. They should point to the new location of your content on the main domain.

Steps to Switch Your Website from a Subdomain to the Main Domain

Start by backing up your website. This protects your data in case something goes wrong during the transition.

Next, move your website's files from the subdomain to the main domain. You can do this using your hosting provider's file manager.

Then, set up 301 redirects from the subdomain to the main domain. This tells search engines that your website has permanently moved.

Finally, update your internal links and sitemap. This helps search engines understand the new structure of your website.

Best Practices for Subdomain Usage

When using subdomains, it's crucial to maintain consistent branding. This helps users recognize that they're still within your website, even if the subdomain serves a different purpose.

Also, ensure that your subdomains don't compete with each other or the main domain for search rankings. This requires careful keyword planning and SEO strategy.


Subdomains can be a powerful tool in your website structure and SEO strategy. They offer flexibility, organization, and the potential for targeted marketing.

However, they require careful planning and management. With the right approach, subdomains can significantly enhance your website's user experience and SEO performance.

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