I've developed web software that I would like to start leasing to companies. It is a javascript program that works as module that only needs linked from their site to utilize.
What are the methods available to secure that the scripts only work for selected clients, paying customers?
I was thinking I could provide them with a code that would need to be verified in my database before printing out the javascript to their page, but after the first fetch they would gain access to the javascript which they could copy and thus never have the need to pay again..