mu4e is an e-mail client for Emacs based on the mu indexer and searcher.
mu4e efficiently handles e-mail searching, reading, replying, moving, and deleting. mu4e is primarily an optimized filter system for the
mailbox. mu4e does not send or fetch email messages, instead relying on other tools, such as
fetchmail and smtpmail. mu4e works well with the gnus message editor to complete features needed for an email client for Emacs.