SSL Certificate for Subdomain – How to Choose the Right SSL Certificate?

An SSL certificate (Secure Socket Layer) is a digital certificate that provides a secure connection between a website and a web browser. It encrypts sensitive information, such as passwords and credit card numbers, and ensures that this information is only accessible to the intended recipient.

A padlock icon in the address bar of a web browser identifies an SSL certificate and the “https” prefix in the URL. The certificate assures visitors that the website is legitimate and their information will be secure.

Having an SSL certificate is becoming increasingly crucial as website visitors become more aware of online security and expect their information to be protected. It is also a ranking factor for search engines, as they prioritize websites with SSL certificates.

Now let us understand something about the subdomain and its universe.

What is Subdomain?

A subdomain is a subdivision of a primary domain name that can be used to organize different website sections into separate, distinct URLs. For example, if your primary domain is “,” a subdomain could be “” or “”

Subdomains can provide a hierarchical structure to a website, making it easier to manage different content areas. They can also host separate websites, such as blogs or e-commerce stores while retaining the main domain’s branding.

Why Do I Need SSL Certificate for Subdomain?

An SSL (Secure Socket Layer) certificate encrypts the data transmitted between a website and its visitors. It is essential for websites that handle sensitive information, such as login credentials, financial transactions, and personal data, to protect this information from being intercepted by malicious actors. For subdomains, an SSL certificate is necessary for several reasons:

  • Security: An SSL certificate helps protect sensitive information from being intercepted and misused by encrypting the data transmitted between the subdomain and its visitors.
  • Trust: An SSL certificate helps build trust with your visitors by demonstrating that you take their security and privacy seriously.
  • Search engine optimization (SEO): Search engines such as Google have stated that having an SSL certificate can positively influence a website’s search engine ranking.
  • Compliance: If your subdomain handles sensitive information, such as credit card information, you may be required by law to have an SSL certificate.

Therefore, it is essential to obtain an SSL certificate for any subdomain that handles sensitive information or for any subdomain that you want to be perceived as trustworthy and secure by your visitors.

How to choose Right SSL Certificate for Subdomains?

When choosing an SSL certificate for your subdomains, it is crucial to consider the following factors:

  • Number of subdomains: Consider the number you need to secure, as this will affect the type of certificate you need. Consider a Wildcard SSL certificate or a Multi-domain SSL certificate if you have multiple subdomains.
  • Validation level: Choose an SSL certificate with an appropriate validation level, such as Domain Validation (DV), Organization Validation (OV), or Extended Validation (EV), based on your security and validation needs.
  • Encryption strength: Choose an SSL certificate with minimum encryption strength of 256-bit to provide adequate security for most websites.
  • Compatibility: Ensure that the SSL certificate is compatible with your web server software and the browsers you want to support.
  • Issuing authority: Choose a trusted and reputable SSL certificate issuer, such as RapidSSL, DigiCert, or Comodo.
  • Price: SSL certificates price vary, so consider your budget when selecting.
  • Support: Ensure that the SSL certificate provider offers adequate help, including installation and technical assistance.
  • Warranty: Consider the level of security offered by the SSL certificate provider, which may protect you in case of data breaches or unauthorized certificate usage.

Ultimately, the right SSL certificate for your subdomains will depend on your specific needs and requirements. Therefore, speaking to an SSL certificate provider for more guidance is recommended.

Types of Subdomain SSL

Wildcard SSL Certificate: A Wildcard SSL certificate allows you to secure unlimited subdomains under a single certificate. It is suitable for websites with multiple subdomains that need to be confirmed.

Multi-domain SSL Certificate: A Multi-domain SSL certificate allows you to secure multiple subdomains and domains under a single certificate. It is suitable for websites with multiple subdomains and domains that need to be secured.

Is It Possible to secure my Domain and Subdomain with a single SSL certificate?

The answer is yes. You can secure the main domain and its first level of subdomains with a single wildcard SSL certificate. A wildcard certificate with an asterisk (*) allows for securing unlimited subdomains under a main domain. For example, * can secure,,, etc.

Things to Consideration While Choosing SSL Certificates for Subdomains

#1. Certificate Authority (CA)

The certificate authority (CA) you choose should be authenticated and reputed in the SSL industry. A reputed SSL certificate authority can assure you that the certificate you purchase is of high quality and secure. The reason to choose reputed CA is it comes with many benefits and featured products.

#2. Subdomains

The number of subdomains also affects the choice of SSL certificate. If you have, a main domain and its first level of subdomains then, a wildcard SSL would be a good choice. On contrary, if there are different levels of subdomains and domains then, a multi-domain SSL would be a good choice.

#3. SSL Validation

There are domain validation, Organization validation, and extended validation level and it influences the selection of a certificate. For an e-commerce website, you can go with an EV SSL certificate, and for basic security; you can go with DV SSL.

#4. Multi-Server SSL

Multi-server SSL is not ideal for wildcard SSL. It is a single certificate that can secure subdomains and can be easily installed on a different server.

#5. Easy Certificate Management

When you select certificate for subdomains, you do not need to worry about certificate management as a single certificate with an expiry date can be easily managed.


SSL certificate for subdomains provides flexibility, security and easy management. Moreover, such a certificate offers better protection, easy renewal, and better search engine ranking. It is a cost-effective way to secure subdomains.

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