Through variants of a concept known as “hooks,” many of its settings can be changed based on criteria such as current mailbox or outgoing message recipients. It allows for changing all the key bindings and making keyboard macros for complex actions and the colors and layout of most of the interface. Mutt has hundreds of configuration directives and commands. However, Mutt still relies on external tools for composing and filtering messages. Later, support for fetching and sending email via various protocols such as POP3, IMAP, and SMTP was added. According to the Mutt homepage, “though written from scratch, Mutt’s initial interface was based largely on the ELM mail client.” New to Mutt were message scoring and threading capabilities. Mutt was originally designed as a Mail User Agent (MUA) and relied on the locally accessible mailbox and sendmail infrastructure.

It also includes MIME support, notably full PGP/GPG and S/MIME integration. Mutt supports most mail storing formats (notably mbox and Maildir) and protocols (POP3, IMAP, etc.).

The Mutt slogan is “All mail clients suck. It was originally written by Michael Elkins in 1995 and released under the GNU General Public License version 2 or any later version. Mutt is a text-based email client for Unix-like systems. Most of the text in the introduction is ripped from Wikipedia. Setting up the Mutt mail client with Protonmail

Protonmail mail