I have written a web app that does this so you can share links which have the same state. You can't have that long of URLs actually - especially for some browsers.

Having to base64 encode most/all of it so you can safely use any kind of data makes it even worse.

My use case was very basic and I quickly hit limits that made it so I couldn't "persist" all of the data I wanted.

Er, you'd store the data in your DB of course and only a comparatively small, encrypted index to it in the URL. You wouldn't trust the client to "persist" the data anyhow.

The question was about storing state in the URL. You are referring to storing a session I’d in the URL. Quite different.

I really hope y'all are aware that URLs generally aren't treated as secret, but authenticated session state should be treated as secret.

I think the poster is referring to things like "offline Google Docs editing that can survive a browser shutdown or crash" which would be... difficult... to cram into a URL ;)