What Is a Subdomain? (And When Should You Use One?)

Short answer

A subdomain is a prefix that extends your main domain, like shop.yourbusiness.com or blog.yourbusiness.com. Use them to host separate parts of your business on the same domain, each with its own purpose or platform.

Examples of subdomains

blog.company.com — blog on a different platform (e.g., WordPress vs main Webflow site)
shop.company.com — eCommerce store (e.g., Shopify) separate from main site
app.company.com — web application behind login
support.company.com — customer support portal (e.g., Zendesk)
mail.company.com — email server
staging.company.com — test version of your website

Subdomain vs subfolder — which is better for SEO?

This is one of the most debated SEO questions.

Subfolder (recommended): yourdomain.com/blog

Google treats it as part of your main site
Blog posts build authority for your main domain
Content and backlinks strengthen the same domain

Subdomain: blog.yourdomain.com

Google may treat it as a separate site
Authority doesn't flow as freely from main domain
Harder to rank for competitive terms

Use subfolders for SEO-driven content (blog, guides, resources). Use subdomains for separate products or platforms (your app, store, or support system).

How to set up a subdomain

Log in to your domain registrar (Namecheap, GoDaddy, Cloudflare, etc.)
Go to DNS management for your domain
Add a new DNS record:
- Type: CNAME (points to another domain) or A (points to an IP)
- Name: blog (this becomes blog.yourdomain.com)
- Value: wherever you're hosting that subdomain
Wait for DNS propagation (a few minutes to 48 hours)

Common subdomain setups

Shopify on a subdomain:

Add a CNAME record: shop → shops.myshopify.com
Configure in Shopify under Domains settings

WordPress blog on a subdomain:

Install WordPress on your hosting server in a /blog folder
Add an A record pointing blog to your server IP

When to use a subdomain

✅ You're using a completely different platform (Shopify, HubSpot, Zendesk) ✅ You have a separate app that requires login ✅ You need a staging/test environment