I wrote a mail client, console-based, with integrated Lua-based scripting. I had to resolve the same problem you mention here. Me? I chose to support Maildir

I wrote a mail client, console-based, with integrated Lua-based scripting. I had to resolve the same problem you mention here. Me? I chose to support Maildir. Exclusively. With nothing else. It kills the client for some users, who want IMAP, etc, but for me it works well. http://lumail.org/ http://lumail.org/ I think with the right abstractions you can go far, but using Maildir to get started isn't a bad choice. SQLite will suffer if you have many many many messages. I know that having handled large email volumes in the past.