Fair use
The key is not technically protected, and I count on fair use.
I run Nielix alone, and I would rather spend my time making the software better than building locks. That is why the server only checks that a key is genuine and has not expired. It does not ask who uses it, and there are no hidden remote locks.
One subscription, one server
A key is for one server and everyone in your household who uses it. You may not use it on other servers, share it with other households or sell access.
Keep the key to yourself
Do not post the key on public sites or in forums. If it spreads, I may have to issue new keys and let the old one expire.
I do not look over your shoulder
The server sends nothing about what is played. On its own it only does two things: it fetches your key, and, unless you have turned it off, it sends a small, anonymous statistic once a week. The statistics are on by default and easy to turn off. They contain only coarse numbers, such as which version you run and which features are used, never titles, file names, users or what you watch, and they cannot be tied to your account. I can see how many servers are connected to your account and when they last fetched a key. You only send an error report yourself, and you can see exactly what is sent. The whole list of what the statistics contain is on the page "What I collect".
I know it can be bypassed
The server is a program that runs at your place, and anyone who wants to can remove the licence check. I know that, and I have chosen not to make it a fight. I could spend months making it harder, but it would be a fight without end that I cannot win anyway, and it would take time away from making Nielix better. Instead I trust you. If you use Premium and like Nielix, pay for it. The price is low precisely so that it is easy to do the right thing. It is that payment that lets me keep developing it. If you cannot afford it, or you have a special situation, write to me.
If I see signs of misuse
I write to you first. It is almost always a misunderstanding, and we find a solution.
In short: pay for what you use, and do not share your key. We handle the rest on trust.