Hello guys, i worked on a trading bot for quite some time and finally its giving pretty good consistent results and i want to publish it on another website. my question here is:

how to create an add-on for ninjatrader in which you cannot use the bot if the subscription has expired?

kind regards

I would recommend contacting NinjaTrader. They make a software licensing solution available to their software vendors. This would probably be the easiest route. Keep in mind, though, that the nature of C# makes it very difficult/impossible to 100% bulletproof against cracking - even for obfuscated assemblies.