Setting up subdomains: complete guide

A subdomain is a prefix for your main domain, like blog.example.nl or shop.example.nl. Subdomains are useful for separating different parts of your website. In this article, we explain how to set up subdomains and when to use them.

What is a subdomain?

A subdomain is an extra level in your domain name structure:

[subdomain].[domain].[tld]
blog.example.nl
shop.example.nl
app.example.nl

The "www" you often see is technically also a subdomain: www.example.nl.

What are subdomains used for?

1. Different websites or apps

Many companies use subdomains for:

blog.example.nl - Company blog
shop.example.nl - Webshop
app.example.nl - Web app or customer portal
help.example.nl - Helpdesk or knowledge base

2. Language or country versions

nl.example.com - Dutch version
de.example.com - German version
uk.example.com - British version

3. Test and development environments

staging.example.nl - Test version
dev.example.nl - Development environment
beta.example.nl - Beta version

4. APIs and services

api.example.nl - API endpoint
cdn.example.nl - Content delivery

Subdomain vs subdirectory

Aspect	Subdomain	Subdirectory
URL	blog.example.nl	example.nl/blog
SEO	Separate entity	Part of main site
Hosting	Can be separate	Same hosting
Complexity	More setup	Simpler

When subdomain:

Completely different website or application
Separate hosting needed
Own SSL certificate required

When subdirectory:

Content belongs to main website
Want to bundle SEO value
Simple management

How to set up a subdomain?

Via your hosting control panel

Most hosting providers offer a simple interface:

Log in to your hosting provider
Go to "Domains" or "Subdomains"
Click "Add subdomain"
Enter the name (e.g., "blog")
Choose the folder the subdomain points to
Save

The subdomain is usually active within minutes.

Via DNS records

If you want more control or point to an external server:

Log in to your registrar or DNS provider
Go to DNS management
Create a new A-record or CNAME-record:
- A-record: blog.example.nl → 123.45.67.89
- CNAME: blog.example.nl → hostingplatform.com

Wait for propagation

Like normal DNS changes, it can take 1-48 hours for the subdomain to work everywhere.

SSL for subdomains

Each subdomain needs its own SSL certificate. Options:

1. Separate certificates

Request a separate (free) Let's Encrypt certificate for each subdomain.

2. Wildcard certificate

A wildcard certificate (*.example.nl) covers all subdomains. Convenient with many subdomains, but often more expensive.

3. Multi-domain certificate

One certificate for specific subdomains. Good middle ground.

Common problems

"Subdomain doesn't work"

Check if DNS propagation is complete (whatsmydns.net)
Verify the DNS record is correct
Ensure the target folder exists at your hosting

"SSL error on subdomain"

Subdomain has no or wrong SSL certificate
Request a new certificate for the subdomain

"Subdomain shows wrong content"

Check directory settings
Check if there's no active redirect

Frequently asked questions

How many subdomains can I create? Technically unlimited. Practically it becomes unmanageable above 10-20.

Does a subdomain cost extra money? No, subdomains are free. Only a wildcard SSL may cost extra.

Does a subdomain affect my SEO? Google sees subdomains as separate websites. SEO value is not automatically shared. For content belonging to your main site, a subdirectory is better.

Can I point a subdomain to an external service? Yes, via a CNAME record. Think of Shopify, Webflow or other platforms.

Also read how to redirect a domain if you want to direct traffic from one address to another.