Hi Frank, Yeah that will work except there is one flaw. Say for example I purchased your plugin so my email address is in your database. Now, I can give out the plugin to anyone together with my email address and they will be able to use it.
To avoid this you need to have a system that keeps track of activation. So if an email address or "serial key" has been used once then it can't be used anymore Or if you are selling a 3 site license then it can be used on 3 sites only.
I have developed a system that takes care of all these and am using it for one of my plugins at the moment. This is how it works:
- When someone purchase this product eStore knows that this product needs a license key so it talks to my license manager plugin and creates a license key.
- The customer get the product with a key in the email.
- The customer can activate this product on his/her site using the serial key
- At activation time the product communicates with the license server to validate the key
- The license manager keeps track of how many times a key is used and on what sites and stuff like that.