Https://remotestorage.io/ was a protocol intended for this. IIRC the visison was that all applications could implement this and you could provide that application with your remotestorage URL, which you could self host. I looked into this some time ago as I was fed up with WebDAV being the only viable open protocol for file shares/synchronization (especially after hosting my own NextCloud instance, which OOMed... - Source: Hacker News / 13 days ago

Not to be confused with https://remotestorage.io/. - Source: Hacker News / 6 months ago

This doesn't support the various consumer cloud storage APIs, but you've just reminded me of a project I ran into years ago that seems to still be around: https://remotestorage.io/ There's also Solid which attempts to do something similar: https://solidproject.org/. - Source: Hacker News / 6 months ago

I have seen one web app uses the remote storage library. It does fit your criteria, but I don't think there is much traction yet. [0]: https://remotestorage.io/. - Source: Hacker News / 6 months ago

RemoteStorage https://remotestorage.io/ seems to be trying to do this too I also really like the https://sandstorm.io approach which goes a little farther beyond. - Source: Hacker News / 7 months ago

Oh I found it. It's learn-anything.xyz. Source: over 1 year ago

I think I found something that looks and works like what you described: https://learn-anything.xyz/. If it's not that one then I'd also like to know what it is because it sounds really useful haha. Source: over 1 year ago

This one is my favourite, its not great for everything but most of the time it provides a solid road map to learning something new. https://learn-anything.xyz/. - Source: Hacker News / over 1 year ago

Learn Anything : Community curated knowledge graph of best paths for learning anything. - Source: dev.to / over 1 year ago

You may be thinking of https://learn-anything.xyz/. - Source: Hacker News / over 1 year ago