I wish there was some browser solution for apps like this where you could save and share your app state between your own devices, and push/share that state with others, all without any server backend involvement e.g. so you could have a Kanban board shared with others and the state would be stored locally and/or in bring-your-own cloud storage.

There's so many apps like this that could be simple, but for robust state saving involve setting up and maintaining a backend (e.g. with security patches, backups, performance monitoring). There's also the privacy implications on your data being store on someone's server, and the risk of data leaks.

It's like there's a key part of the internet that's missing.

Something like this could be a browser extension? This exists?