how to protect your wp plugin or wp theme?

Hi! I’m interesting to know methods how to protect your code on codecanyon???
I see there some plugin only available for one domain and some themes asks activation code.
How we can do this???

where is documentation to read how to do?

Envato API is perfect for themes or plugins to check the user’s purchases with code, but it’s not possible if you sale standalone items which do not have install process (which is my case).

That’s why I worked on this tool to send DMCA takedown notice. I found some of my items were shared illegally, and didn’t find any efficient affordable tool to send DMCA.