Interesting! Will try this soon, I have very similar gripes with nextcloud et al that you mentioned. The lock in to postmark I don't love, I think I would rather have it be a SMTP+IMAP "proxy" so I can use my existing email service within the suite of apps seamlessly.
yep i know postmark wont be everyone’s fave. i’ve abstracted all that to a single golang interface so it’d be easy to swap out. i’ll probably write a pure SMTP version as an example soon