Some anecdata as a hey.com user myself: It feels like they've optimized a lot for initial load of the main homepage (The "Imbox"). Obviously this is super impor

Some anecdata as a hey.com user myself: It feels like they've optimized a lot for initial load of the main homepage (The "Imbox"). Obviously this is super important for an e-mail app... but once you start trying to load anything older than the most recent ~20 e-mails (Eg scrolling "The Feed"), then the load times can be horrifically slow (>10s, followed by a janky pop-in of HTML suddenly loaded). I'm not sure if this is caused by this technology in particular or if there's some kind of cache miss happening here, but coming from and comparing to gmail - which hey's makers like to dump on regularly - the performance is miserable. Sure, the number of transferred bytes is small and there's not a lot of JS to load - both of which I'm a big fan of, but the actual load time that I feel as a user is pretty bad for these AJAX calls. Overall I'm a fan of what they're trying to do with Hey.com, but this particular use case feels like a big UX miss to me.