Firebase looks really cool, but my first impression the moment I see that you end up building everything in a way where it is tightly coupled to the servers of a startup that does not have years of profitability yet (or even published pricing), is that there's no way I'd put anything but toy/demo's on it for a <i>long</i> time.<p>It <i>seems</i> like the type of thing that'd do great with the option of a self-hosted server, and it also seems like the type of thing that'll see open source clones of pretty quickly, though. But I'd actually be vastly more comfortable paying Firebase to host my apps if I knew there was an open source fallback for their server component.