I’ve been thinking about this more and more. According to the sidebar, this community is “A place to share alternatives to popular online services that can be self-hosted without giving up privacy or locking you into a service you don’t control.” Based on that I don’t think Plex qualifies.
Privacy: Plex clearly records the metadata of what you watch. When I used it, it would send me a report by email of what my “friends” were watching. Even with that turned off, their services still track telemetry.
Control: Plex has all of it. They can (and do) make unilateral changes to the service, how authentication works, where you can run it, etc.
So I ask, when you are hosting something that is entirely dependent on a commercial entity to function, is Plex really selfhosting in the spirit of this community?
I agree that it doesn’t fit the definition in the sidebar, and I don’t use it because of those issues. If I’m self-hosting something, it’s precisely because I don’t want to be sharing data with a company (whether it be my photos or an inventory of my media library) or because I want more control than an external service provides.
That said, most stuff we self-host isn’t going to be completely independent, e.g. if you’re running anything with HTTPS, you’ll need Let’s Encrypt or another way of obtaining a valid cert (unless you want to get into the habit of allowing exceptions in your browser, which is not a good idea).
In the strictest sense, Plex does qualify as self-hosting (you’re running the application on hardware you manage along with your own media library) - but I’d argue that the compromises it requires are not ones every one is willing to agree to.