Subdomain

What is a Subdomain?

A subdomain is an extension of a primary domain that allows different sections of a website to be organised and function independently. It appears at the beginning of the main domain name, separated by a period. For example, in blog.example.com, “blog” is the subdomain of the main domain “example.com.”

Subdomains are commonly used to segment a website’s content, especially when different parts of the site serve distinct purposes. This might include a blog, online store, or customer portal.

Subdomains vs. Subdirectories

Another way to structure sections of a website is through subdirectories (also known as subfolders). Subdirectories appear after the main domain in the URL, such as example.com/blog/, whereas subdomains are placed before the root domain.

Both subdomains and subdirectories can organise content within a website, but they serve different purposes and structures.

Examples of Subdomains

• shop.example.com – used for an eCommerce section
• support.example.com – for customer support
• app.example.com – for a software or tool application

Examples of Subdirectories

• example.com/about-us/ – for an “About Us” page
• example.com/blog/marketing/ – for marketing blog content
• example.com/contact/ – for a contact page

Why Use Subdomains?

Subdomains are useful for several reasons:

1. Separation of Website Functions – Subdomains are ideal for isolating different parts of a business, such as a blog, shop, or support centre, which may require separate platforms or services.
   
2. Staging or Testing – Subdomains like staging.example.com are commonly used to test new features or designs without affecting the live website.
   
3. Targeting International Markets – Many businesses use subdomains to create separate websites for different countries, such as uk.example.com or au.example.com, to offer location-specific content.
   

Challenges of Using Subdomains

While subdomains offer flexibility, they come with some challenges:

1. More Complex Setup – Subdomains can require more technical configuration compared to subdirectories, including setting up DNS records and managing additional security certificates if necessary.
   
2. SEO Considerations – Google treats subdomains as separate entities in some cases, which means they may take a little longer to crawl and index. However, Google has confirmed that subdomains and subdirectories are treated equally for SEO.
   

Best Practices for Subdomains

1. Ensure Proper Internal Linking – Link between your subdomain and main domain so search engines and users can easily navigate all site sections.
   
2. Use Unique Robots.txt Files – Each subdomain should have its own robots.txt file to control crawling and indexing, as Google handles them independently from the main domain.
   
3. Monitor in Google Search Console – If you have subdomains, add them separately to Google Search Console to track performance and issues independently.
   

FAQs

Are Subdomains Better Than Subdirectories for SEO?

No, both options are equally valid in terms of SEO. The choice depends more on your website’s structure and needs.

Are Subdomains Treated as Separate Websites?

If not linked properly, Google might treat subdomains as separate sites. However, with proper internal linking, they are considered part of the main domain.

Do Subdomains Need Separate SSL Certificates?

Some subdomains may require additional SSL certificates, unless a wildcard certificate is in place, which covers all subdomains under a single domain.