I worked as a Full Stack Developer, where I built a website with two main purposes: client management and product management, integrated with a secure payment system.
When a client purchases software from the company, they are required to fill out a form and set a password. An account is then automatically created under their name, along with a unique product ID and product key linked to that account.
This solution ensures that the product key is tied exclusively to the original client. As a result, if someone attempts to copy the program and share it with another person, access will be denied—since the product key only works for the registered client.