I've been using TiddlyWiki5 with Google Firebase for over a year now. It's stable enough to use on a daily basis. There's a detailed walkthrough of how to create your own instance with lots of screenshots. The entire process takes less than 30 minutes: https://neumark.github.io/tw5-firebase/
Please consider this version a proof of concept rather than a polished product! My focus was on multi-device or small-team collaboration:
* Basic authorization (bags have an access policy determining who can read / write them).
* Multiple wikis can be hosted under a single firebase account.
* It uses Firebase's built-in social auth to log in users.
* Tiddlers are written individually with locking, preventing users overwriting each others' updates.
