When you start your subscription from Elegant Themes, you could use the Divi theme or Divi builder on several sites. Once you create your order, you will also have a Divi license and then use it with as many sites as you like.
There are no limitations on how often times a theme may be used. You could obtain the API keys and you could then use API keys to be using the Divi theme many times.
You’ll even have access to other stuff like Bloom, Monarch, Extra, and much more.
When you’re a website agency who is dealing with many clients, the Divi is awesome for you.