Each note has two URLs, with one allowing editing, while the other one has read-only access. If you lose the URL, you essentially lose the note.
The front end polls the API every few seconds, so if you have the same note open in a few tabs you should see it changing as the content changes.
I've been using Mura Notes for a while now and I have a pinned and bookmarked "main" note, where I have links to other notes.
I used Postgres, node.js + express, and next.js + slate.js, and everything's on GCP. Since I'm the only user so far, it takes some time to spin up the instance when I access my notes, which is a little annoying (yet, cheap).
Also, I am an iOS user, so I noticed just recently that the todo editor doesn't work ok on Android, which is a problem with slate since the examples on their site also stuff up the same way. Other than that, I think it all works reasonably well.
Some other things to note are that there's a dark mode (top right) and that if you share a read link and a few people report it as abusive, the read link will stop working. The deletion of a note results in removing its content (and there's no versioning, so it is really gone), not the actual deletion of the link. And that's about it for now.
Future (major) plans include things like one-time pad encryption, where I want to have an option to generate a random key and a text field where users can enter their own and possibly other privacy-related features. Well, I don't track usage through third-parties anyway. Nor do I have any integrations with anything external, so they are sort of private, but of course, I can see the content through the db.
All suggestions welcome, of course.