no, jitsi does not require a membership, just a credential.  you need to have the app, it tokenizes your data stream from your phone or laptop to the jitsi SFU server, and then everyone who has the same "key" which is just the #nameoftheJitsiRooom  they can join.  
you can password a room. make a room "permanent" by always joining it, but the odds of some dippy do taking your room name is pretty low... plus, are you really that weak inside ? pick a new name.
you can also do cool stuff like have some callers dial in on video, some dial in on their phones, and like the voice users will show the phone number, so people on the call can know its them, oh yeah thats bobs number or thats theresa, etc-  its got a few other features, but you should just freaking read about it man :)

they have a website.   jitsi. something :D