What Are Subdomains? How To Use And Optimize Them For SEO?

January 24, 2024 | Technical SEO

When you type a query in a search engine box and hit enter, you get a list of blue links offering the most relevant information satisfying your search query.

Then you click the link (Usually ranking within the first five positions on the SERP, offering a clear meta title and meta description) you find most suitable according to your search query.

When you land on the web page, have you ever noticed an extension appearing before the domain name in the URL? That extension is called a subdomain.

You have been redirected to that page either because your search query includes that term or because the search engine might have been redirected automatically considering the relevance of your search query.

This article shall discuss subdomains, their usage, SEO benefits, and other relevant things you must know about them.

But before that (though you got an idea already),

What Is A Subdomain?

The subdomain is the part of the URL appearing before the root domain name. It acts as an extension of the main domain. 

For example,

Subdomain example

A subdomain helps you organize your website content and allows your website to offer different sections.

However, there are other parts of a complete URL; you must know how subdomains fit within the URL structure.

Subdomain Structure in URL

Let us consider the following example of a URL structure to understand its various components and see how to fit your subdomain into the URL structure.

Components of an URL

Protocol: The HTTP or HTTPS part appears at the beginning of the URL.

Subdomain: The subdomain is the extension that appears between the protocol and the primary domain name (blog is the subdomain name in the above example). However, the most widely used subdomain is ‘WWW’ (World Wide Web).

Second Level Domain (SLD): The second level domain appears between the subdomain and top-level domain. It typically reflects the name of your business or brand.

Top Level domain (TLD): TLD is the part of your domain name that appears after the second level domain—for example, .com, .org, etc.

Pros And Cons Of Using Subdomains for SEO

Pros and cons of using subdomains for SEO


Let us first consider the benefits a subdomain can offer your website,

  1. Subdomains prevent search engines from getting distracted by other products.
  2. The lack of redirects in subdomains helps search engines to focus more on the user’s search intent
  3. Subdomains allow you to create a new website within a website without buying a separate domain name.
  4. Google does the marketing of subdomains separately while keeping in mind that they are the extensions of a known and trustworthy main domain.
  5. Subdomains allow Google bots to crawl and index web pages precisely like they do the same for subdirectories. 
  6. Using subdomains makes your content easy to navigate.
  7. Subdomains allow you to target keywords from other niches without distracting from your website’s main purpose.
  8. They help you target a larger audience and grow authority in various niches by covering different trending topics.
  9. Users can quickly find the content they seek on your subdomains and get engaged, increasing your dwell time.


There are a few drawbacks to using a subdomain,

  1. You need to design a subdomain from scratch, like a brand-new website.
  2. Even after recognizing it as a part of your primary domain, Google considers a subdomain a new website.
  3. You must perform the verification process for each subdomain separately in the Google search console
  4. Subdomains do not get the benefit of your main domain’s authority.

What Is A Subdirectory?

A subdirectory is a folder that contains the content inside your root domain.

For example, you can make your blog page using a subdirectory folder.

Example of subdirectory

Your blog content will be available in that folder sitting inside your primary domain. Subdirectories use the same design and CMS (Content Management System) as your main website.

Subdomain Vs Subdirectory?

Subdomain vs subdirectory

Subdomain Subdirectory
The subdomain is the part of the URL appearing before the root domain name. Subdirectory is the part of the URL appearing after the top-level domain name.
A subdomain is an extension of your primary domain. A subdirectory is a folder that contains content inside the main domain.
The subdomain acts as a separate website that can use a different design and CMS from the main website. The subdirectory uses the same design and CMS as that of the main website.
Subdomains are suitable to offer content that differs from the purpose of your main website. Subdirectories are suitable to offer content that matches the purpose of your primary website.
Subdomains can not benefit from the main domain’s popularity and authority as search engines consider them separate websites. Subdirectories reap the benefits from the authority of your main website.

What Are The Best Uses Of Subdomains?

Now that you know the difference between a subdomain and a subdirectory, you must be eager to know where you can benefit from using subdomains.

Here you go! 

Offering Blogs On Different Topics

If you want to offer blogs on diversified topics that do not relate directly to the main purpose of your website, you must use a subdomain for your blog section.

Using subdomain for blog section

That will help you in the following ways,

  1. You can keep your blog content separate from the clutter of the rest of the website.
  2. Users find it easier to navigate your content.
  3. Users do not get confused seeing content on topics that differ from the main website. 
  4. You can reach a bigger audience by targeting keywords from various niches.

Launching E-Commerce Stores

If you dig deeper, you can find that many ecommerce websites were not meant for selling at the time of their inception.

Many websites begin with a different purpose and start selling products or services at a later stage after gaining a certain amount of online presence and authority

Using separate subdomain for ecommerce store

A subdomain allows you to create an ecommerce store and sell your products, keeping them separate from the main offering of your website.

International Selling

To expand your selling internationally, you can create separate pages to target country-specific audiences using subdomains.

Using subdomain to target country-specific audiences

That also boosts your main website’s authority and trustworthiness to users and search engines.

On the other hand, you need not buy separate domain names and thus can reduce your budget for international SEO.

Targeting New Audiences

You can use subdomains to target different audience segments or achieve various business objectives.

For example, the home page of grav.com allows shopping for all users.

Home page of grav.com allows shoppers to buy products

Meanwhile, the website offers a separate page using a subdomain exclusively for wholesale buyers.

grav.com offering separate page for wholesale buyers using subdomain

Creating Pages For Enhancing Customer Experience

Providing a separate FAQ section for your customers may not be enough to answer all their queries.

Your website must offer a smooth customer experience to ensure client retention. Your website should answer each of the customer questions.

Separate subdomain for the ‘support’ page

You can offer a separate ‘support,’ ‘contact us,’ or ‘help’ page using a subdomain to satisfy customer queries.

Client Portal

You can use a URL subdomain like ‘https://auth.rankwatch.com/signup/free’ to offer a free sign-up portal for your clients.

The RankWatch sign-up page for free trial

That helps users complete a hassle-free sign-up process, avail of the free trial period, and check other details about the tool without contacting your support team.

Building And Testing A New Website

Suppose you are building a new website or migrating your existing website; you can test the new site or the new version of the old website using a separate subdomain.

Testing a website in staging environment I

It is a must to test a new website before going live and submitting it to search engines for crawling and indexing.

In the case of website migration, the subdomain provides a free staging environment for testing new features and fixing errors without hampering your current website’s functionality.

Mobile Optimization

Google prioritizes the mobile version of a website over the desktop version while crawling and indexing.

Hence, it is essential to consider mobile responsiveness while building your new website.

Once you finish building your website, you must run a mobile-friendly test using a reliable mobile-friendly checker tool like RankWatch.

The RankWatch mobile friendly checker tool

If your existing website is old enough and you want to make it responsive for mobile devices, the easiest way to do that is to use a separate domain for the mobile version of your website.

Subdomain m.facebook.com

For example, Facebook uses a separate subdomain, ‘m.facebook.com’ for mobile users. 

How To Optimize Your Subdomains For SEO?

It would help if you considered your subdomains as separate websites while optimizing them for search engines.

It would be best to choose a one-stop solution like the RankWatch tool that offers several features to optimize your subdomains.

Organic Research

The RankWatch Domain Analyzer allows you to conduct a thorough analysis of your subdomains.

The RankWatch Domain Analyzer

The tool provides you with a detailed competitor analysis report showing the list of your main organic competitors.

The RankWatch domain analyzer showing the list of your main organic competitors

It also provides insight into the common keywords they are targeting and the amount of traffic they get from them.

Rank Tracking

Rank tracking helps you monitor the performance of your content on your different subdomains daily.

Rank tracking using the RankWatch tool

You can check the keywords and snippets they are ranking for and measure the share of voice using the rank tracking feature of the RankWatch tool.

Site Audit

Performing a site audit helps you measure the SEO health of your subdomains and identify the technical SEO issues preventing them from ranking higher in the search results.

The RankWatch SEO audit tool

However, you must choose an authentic tool like the RankWatch site auditor to get accurate results.

Site score in RankWatch site auditor

The tool provides you with an overall SEO health score of your subdomain after measuring the technical SEO issues.

Issues distribution report in RankWatch site auditor

The ‘Issues Distribution’ section lists all the technical SEO issues and categorizes them depending on the criticality of the issue.

You need to address the highly critical SEO issues without further delay.

Final Thoughts

Your first investment while making a new website is to buy a domain name, and no website owners think of using subdomains at that stage.

Once you finish building your website, it is time to test it in a staging environment before making it live and allowing search engines to crawl and index your website.

As your website grows with time, you try to expand your reach and audience by tapping into various niches.

That is the time you recognize the need and importance of subdomains.

Subdomains allow you to offer blogs on niches not directly relevant to your main website, make your content easy to navigate, help you open your online store, reach international audiences, enhance user experience, and test new website features in a staging environment.

However, search engines consider subdomains new websites, so you need to start from scratch. Subdomains do not benefit from the hard-earned authority of your primary domain.

That means you need to optimize your subdomains for search engines using authentic SEO tools from the beginning.

However, if you want to avoid covering diversified topics from various niches and want to offer blogs on topics only relevant to your main website, using subdirectories will be sufficient.

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