What is a Subdomain? How to Create and Manage Subdomains on Thai Hosting 2026

A subdomain is a subdivision of your main domain, created by adding a prefix before the domain name — like blog.example.com, shop.example.com, or api.example.com. Subdomains are a fundamental tool for organizing complex websites, separating different services, and managing staging environments. This guide covers everything you need to know about subdomains on Thai hosting.

What is a Subdomain?

In DNS structure, a subdomain sits before the Second-Level Domain (SLD) and Top-Level Domain (TLD). For example.com, common subdomains include:

• blog.example.com — Blog subdomain
• shop.example.com — Online store
• staging.example.com — Testing environment
• api.example.com — REST API endpoints
• docs.example.com — Documentation site
• mail.example.com — Email server reference

Subdomains are essentially separate websites that share your main domain name, making them easier to remember and trust than entirely separate domains.

Why Use Subdomains?

• Service separation: Blog, shop, and app can operate independently without interfering with each other.
• Staging environments: Test new code on staging.example.com before deploying to production.
• Multiple CMS/frameworks: Main site on WordPress, shop on separate WooCommerce, API on Laravel — each on its own subdomain.
• Separate SSL management: Issue individual SSL certificates per subdomain, or use Wildcard SSL to cover all at once.
• Separate analytics tracking: Track traffic for each subdomain independently.

Creating Subdomains in DirectAdmin

1. Log in to DirectAdmin → Go to Domain Setup or Subdomain Management.
2. Enter the subdomain name (e.g., "blog" — the system creates blog.yourdomain.com automatically).
3. Choose the Document Root directory for this subdomain's website files.
4. Click Create — the subdomain is ready immediately.

DNS Records for Subdomains

When you create a subdomain through DirectAdmin, the system automatically creates an A Record in DNS pointing the subdomain to the same server IP. If you need to point a subdomain to a different server, you'll need to manually update DNS records:

• A Record: Points the subdomain to a specific IP address.
• CNAME Record: Points the subdomain to another hostname (e.g., Cloudflare Pages, GitHub Pages, or an external service).

SSL for Subdomains

Each subdomain needs its own SSL certificate. Two approaches:

• Let's Encrypt per subdomain: In DirectAdmin → SSL Certificates, issue a free Let's Encrypt certificate for each subdomain individually.
• Wildcard SSL (*.example.com): Covers all subdomains in a single certificate — more cost-effective when managing many subdomains.

Installing WordPress on a Subdomain

1. Create the subdomain in DirectAdmin (e.g., blog.example.com) with a dedicated document root.
2. Create a new database in MySQL Management for this subdomain.
3. Upload WordPress files to the subdomain's document root.
4. Run the WordPress installer at http://blog.example.com/wp-admin/install.php
5. Issue an SSL certificate for blog.example.com via SSL Certificates.

Subdomain vs Subfolder: Which is Better for SEO?

A common SEO debate: blog.example.com (subdomain) vs. example.com/blog (subfolder)?

Google officially treats both equally, but in practice, subfolders often have practical SEO advantages:

• Link equity from the main domain flows directly to content
• Google doesn't need to crawl a separate domain
• Blog posts benefit fully from the main site's domain authority

Use subdomains when services are fundamentally different from the main site (apps, APIs, staging environments, completely separate products).

Popular Subdomain Use Cases

• blog.domain.com — Content marketing blog
• shop.domain.com — E-commerce store separate from corporate site
• app.domain.com — Web application or SaaS product
• staging.domain.com — Pre-production testing environment
• api.domain.com — REST API endpoints
• docs.domain.com — Product documentation
• support.domain.com — Help desk or ticketing system

Frequently Asked Questions