[vorador]

The main reason is that you need to be backward compatible with 30 years of terrible hacks. That's why there's a ton of vaporware email clients --- there's a huge amount of work that most of your users don't suspect.

Full-disclosure: I work at a company building an open source email client (https://nylas.com/N1) and an API to simplify email (https://nylas.com/docs)

[rabblac]

Well, it's from some time that I've been looking for a modern and open source email client, but N1 looks very promising.

Little question: do you plan to support PGP?

[grinich]

It's in development by several N1 users: https://github.com/nylas/N1/issues/96