We need at least two servers when managing a product: a development server and a production server.
A good way to get started with a development server is to use a LEMP droplet on DigitalOcean.
We can add new domains using:
certbot --nginx -d example.com -d www.example.com
Then we can set up virtual hosts as explained here.
We can repeat the process to add more domains. The new domains are automatically set up at