A lot of this will depend on your language/environment. There exist client-libraries for IMAP, POP, etc. But if you don't have those then implementing them wi

A lot of this will depend on your language/environment. There exist client-libraries for IMAP, POP, etc. But if you don't have those then implementing them will not be so difficult. The truly hard part is dealing with emails themselves, both in terms of MIME, and the bastardized broken things people will send you - malformed headers, missing headers, etc, etc. I wrote a modal console-based Email client, completely scriptable via lua: http://lumail.org/ http://lumail.org/ It was more work than I expected, but also fun. So there are compensations. (Obviously graphics make things harder, with threading, etc, but if you can handle the core you should be able to wrap a GUI around it.)