Client Licence Management - Integration into my website

Hello everyone. 

I have a website in construction (https://lemchart.com/) where i would like to sell my trading bot. 

There will be a stripe checkout for people who want to buy. After that, people need to be able to generate a key to activate the EA. Of course you can suggest me alternative if you think that it's good for me. 

It need to be simple ! 

Thank you.