Thanks! IMAP account support is something I would really like to add (and Mimestream already uses IMAP for some specific operations where it is a better fit), but from past experience I know that it is complicated ;)
I'm also really keen on adding support for JMAP and Office 365 I the future.
Excited that you're considering JMAP! Hopefully it solves some of the pain-points of implementing IMAP and makes it easier to deliver a great UX. If e.g. Mimestream can deliver as good a UX with a Fastmail account (or Cyrus IMAP or Dovecot installation) as it does with a Gmail account, I think it will help the independent email ecosystem. (Though there is a big headwind, so I understand focusing on Gmail now.)
Edit: downloaded the beta. Will give it a shot with my work G Suite account.
I am really excited about adding support for JMAP – I participated in the IETF WG for it, gave some feedback, and think it's a very well-designed protocol that should be really efficient at syncing email. It would probably be one of the most fun features for me to add to the app, but yeah, there's still a lot of work left for the Gmail account experience first.
Adding JMAP would be a definite +1 for me. I use fastmail and their web interface is good and mobile app is better.
I use Thunderbird on my Mac because I need things like smart signatures that are dependent on my outgoing email address but I want a combined Inbox.
A native app that supports JMAP and provides that sort of integration would let me migrate from Thunderbird, which while it's been awesome for the years I've used it, is showing its UI age.
Is there a list of shortcuts somewhere? All I see is the choice for Default, Apple Mail, or Gmail. And only about half of the Gmail shortcuts I tried seem to work.
Support for both Gmail and Office 365 with their own proprietary APIs would be a knockout feature. Also I really appreciate the fact you don't use any intermediary servers, which has held me back from using some other macOS email clients.
1. It's wicked fast (seriously) 2. It has Gmail style shortcuts
The only thing I wish it had was a generic IMAP support for some of my other accounts. Either way I've been liking it!