Astupidmoose on Nostr: What is my best option for running a nostr relay in terms of software? I've seen paid ...

What is my best option for running a nostr relay in terms of software? I've seen paid relays popping up, but what about private relays where I can add people via an API based or some other trigger?

My idea is to host a @Coincards specific private relay. If you're a past coincards customer, you get access to this "paid" relay for free.

Is this possible?