I've spent the last two years building a new email client
No offense but unless it’s a 1st party client email clients are something that is very hard to trust.<p>Who controls your client has access to your inbox with most services even the few that have separate IMAP&#x2F;POP3 passwords like Hushmail can be compromised through it.<p>If your client also integrates with encryption or worse takes charge of it my encryption key is also now at risk.<p>Lastly since email today is pure HTML you also inherit all the possible vulnerabilities that come with having a DOM parser and a layout engine and even modem browsers still get both wrong.<p>And using something like Electron or even Chromium won’t implicitly save you because the way you implement them matters a lot and now you are tied with their update cycle which might break functionality forcing you to manually backport security fixes which is hard to accomplish.<p>So unless you have the source or show an audit from a respected firm (c53, isec etc.) its going to be quite hard to recommend to anyone to take the dive and try this out.