The proxy is a pretty crappy Perl JMAP server layered on top of a middling quality IMAP sync layer. The CalDAV/CardDAV bits are a bit better because it has nic

The proxy is a pretty crappy Perl JMAP server layered on top of a middling quality IMAP sync layer. The CalDAV/CardDAV bits are a bit better because it has nicer synchronisation primatives, but it's still code I slapped together over a couple of weeks of evenings. It's fine for playing with, but I wouldn't try to use it for large mailboxes. There's not much optimisation in there, it's doing pretty basic sqlite queries against a fairly normalised database, so there's no denomalisation for efficiency.