How to create subdomains for your server

A subdomain (for example app.example.com) lets you run several services under the same domain. It is created with a single DNS record.

1. Add an A record

In the domain's DNS panel, add:

app.example.com.   A    203.0.113.10

The subdomain can point to the same server as the main domain or to another one.

2. Configure the web server

In Nginx, add a server block with server_name app.example.com, see How to host multiple sites.

3. Add HTTPS

Each subdomain needs its own certificate (or a wildcard one), see Free SSL certificate.

Wildcard subdomain

To catch any subdomain at once:

*.example.com.     A    203.0.113.10

Useful for apps that create subdomains per customer. Check propagation with the DNS propagation guide.