The Difference Between Subdomains and Subdirectories for SEO; How to Use Reverse Proxies to Resolve Subdomain Issues
In SEO (search engine optimization), the choice between subdomains and subdirectories can have a real impact on a website's ranking and traffic performance, despite Google's official claim that there is no significant difference between the two in terms of SEO.
🧠 I. SEO Differences Between Subdomains and Subdirectories
What are Subdomains and Subdirectories?
- Subdomain:
Example: blog.example.com
A “separate website” under the main domain, treated by search engines as an independent site. - Subdirectory:
Example: example.com/blog
A directory under the main site, part of the same website structure.
Differences in Actual SEO Performance
✅ Actual experience shows:Placing content in a subdirectory often results in 2x-3x better natural SEO performance, especially in the early stages or when aiming to share weight with the main site.
🔄 II. Map Subdomains to Subdirectories Using a Reverse Proxy
To balance flexibility in development and deployment (such as deploying blogs or applications on independent servers or systems), you can use a reverse proxy to “map” subdomain content to subdirectory paths on the main domain.
🛠 Example: Using Nginx to implement Subdomain -> Subdirectory mapping
Scenario:
- You have a blog system at blog.example.com
- You want users to be able to access it via example.com/blog/
🔧 Nginx configuration example:
server { listen 80; server_name example.com; location /blog/ { proxy_pass http://blog.example.com/; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; # Prevent path confusion;
proxy_redirect off proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_set_header X-Forwarded-Proto $scheme; # Clean up subdirectory paths (optional, depending on application support);
sub_filter_once off sub_filter 'href="https://capgo.ai/blogs/' 'href="https://capgo.ai/blogs/blog/'; sub_filter 'src="https://capgo.ai/blogs/' 'src="https://capgo.ai/blogs/blog/';
}
}
