As you all know, I handle my email with mu4e and am very happy with it. But it’s not the only possibility. Notmuch and Gnus are popular choices but there’s also the builtin Rmail. It doesn’t get a lot of attention and many are only vaguely, if at all, aware of it.
Ben Card is an Rmail user and finds that it meets his needs well. He likes its simplicity and easy configuration. He’s got a post that describes how he uses Rmail, his configuration for it, and how to implement multiple accounts. He also has links to two videos (1, 2) where he covers the same material.
If you’re interested in finding out more about Rmail, I’d watch the to videos before reading the post. After doing all that, my conclusion is that mu4e (and probably any of the other apps) is a better solution. One of the great features of mu4e—one might even say its whole point—is its powerful search capabilities. Following Ben Maughan, I put all my saved emails in a single file and use search to find whatever I need. It’s simple and powerful and I don’t have to decide where to put each email or remember where I put it if I need to retrieve it. Rmail lets you store your emails in separate files but doesn’t—as far as I can see—have an integrated search function.
Configuring multiple accounts is fairly simple but seems a bit ad hoc. It boils down to writing functions that set Rmail’s environment for a particular account. Card shows how to do this in detail in the second video.
Still, if you’re looking for a simple, lightweight email client that runs under Emacs, it’s worth taking a look at Rmail.
Update : GNUS → Gnus