Subdomain

A subdomain is a separated part of a domain name placed before the main domain and divided from it by a dot. In the address shop.yourcompany.com, the segment shop is a subdomain of the domain yourcompany.com. Subdomains let you create distinct, logically separated addresses within a single registered domain, without having to buy additional names.

How a subdomain works

A subdomain is handled by the DNS system, just like the main domain. For a subdomain to start working, an appropriate record must be added to the DNS zone, pointing to where its content lives:

• A record — directs the subdomain straight to the server's IP address (A record);
• CNAME record — directs the subdomain to another domain name, for example an external service (CNAME record);
• wildcard record — handles all unspecified subdomains with a single entry.

A subdomain can point to the same server as the main domain or to entirely different hosting, so different parts of a site can run independently. The structure is hierarchical, and in theory you can nest further levels, such as panel.client.yourcompany.com.

Practical application

Subdomains are used to organize a site and separate its functions. Typical examples are blog.company.com, shop.company.com, panel.company.com or help.company.com. Companies use subdomains for language versions, staging environments, client panels and applications hosted with external providers. In most hosting plans, creating subdomains is available without limits from the control panel.

From an SEO perspective, it is worth remembering that search engines often treat a subdomain as a separate site, which means its authority builds up partly independently of the main domain. The decision whether to place a new section on a subdomain or in a directory of the main domain should therefore take into account your positioning strategy and how the content is meant to be linked.