My mail (mu4e) configuration section of .spacemacs

mu4e-config-emacs

;; Mu4e ------------------------------------------------------------------------
  ;; Mail Mu4e

  (require 'org-mu4e)

  (setq mu4e-maildir "~/Mail")

  (setq mu4e-user-mail-address-list '("jack@fusionary.com" "jack@baty.net") )
  ;;store link to message if in header view if nil - header query if t
  (setq org-mu4e-link-query-in-headers-mode t)
  (setq mu4e-change-filenames-when-moving t)
  (setq mu4e-view-prefer-html nil)
  (setq mu4e-attachment-dir "~/Desktop")
  (setq mu4e-use-fancy-chars nil) ;;
  (setq mu4e-view-show-addresses t) ;; I prefer to see both name and address
  (setq mu4e-compose-keep-self-cc nil) ;; Don't include my address on CC when replying
  (setq mu4e-compose-dont-reply-to-self t) ;; trying because the above doesn't work
  (setq mu4e-headers-sort-direction 'ascending)
  (setq mu4e-enable-notifications nil)
  (setq mu4e-alert-style (quote osx-notifier))
  ;;(setq mu4e-compose-complete-only-personal t)
  (setq mu4e-compose-complete-only-after "2012-01-01")
  ;;(setq mu4e-compose-in-new-frame t)
  (add-to-list 'mu4e-view-actions '("ViewInBrowser" . mu4e-action-view-in-browser) t) 
  (setq mu4e-sent-folder "/Fastmail/Sent")
  (setq mu4e-drafts-folder "/Fastmail/Drafts")
  (setq mu4e-refile-folder "/Fastmail/Archive")
  (setq mu4e-trash-folder "/Fastmail/trash")
  (setq mu4e-get-mail-command "/usr/local/bin/mbsync -a")
  (setq message-send-mail-function 'smtpmail-send-it)
  (setq send-mail-function 'smtpmail-send-it)
  (setq message-send-mail-function 'smtpmail-send-it)
  (setq smtpmail-smtp-server "smtp.fastmail.com")
  (setq smtpmail-smtp-service 465)
  (setq smtpmail-stream-type 'ssl)


  (add-hook 'mu4e-compose-mode-hook
            (lambda ()
              (set-fill-column 72)
              (auto-fill-mode 0)
              (setq mu4e-compose-format-flowed t)
              (setq visual-line-fringe-indicators '(left-curly-arrow right-curly-arrow))
              (visual-line-mode)
              ))

  (setq mu4e-maildir-shortcuts
        '(("/Fastmail/INBOX"    . ?i)
          ("/Fastmail/SaneLater" . ?l)
          ))

  (setq mu4e-bookmarks
        `(("flag:unread AND NOT flag:trashed" "Unread messages" ?u)
          ("date:today..now" "Today's messages" ?t)
          ("maildir:\"/Fastmail/Sent\" date:1d..now"       "Sent recently"     ?r)
          ("flag:flagged"       "Flagged messages"     ?f)
          ("date:7d..now" "Last 7 days" ?w)
          ))

(setq mu4e-contexts
    `( ,(make-mu4e-context
          :name "Work"
          :enter-func (lambda () (mu4e-message "Entering Work context"))
          :leave-func (lambda () (mu4e-message "Leaving Work context"))
          ;; we match based on the contact-fields of the message
          :match-func (lambda (msg)
                        (when msg
                          (mu4e-message-contact-field-matches msg
                            :to "@fusionary.com")))
          :vars '( ( user-mail-address      . "jack@fusionary.com"  )
                   ( user-full-name         . "Jack Baty" )
                   ( mu4e-compose-signature . nil)
                   ))
       ,(make-mu4e-context
          :name "Personal"
          :enter-func (lambda () (mu4e-message "Switch to the Personal context"))
          ;; no leave-func
          ;; we match based on the contact-fields of the message
          :match-func (lambda (msg)
                        (when msg
                          (mu4e-message-contact-field-matches msg
                            :to "jack@baty.net")))
          :vars '( ( user-mail-address       . "jack@baty.net" )
                   ( user-full-name          . "Jack Baty" )
                   ( mu4e-compose-signature  . nil)))))

 (setq mu4e-context-policy 'pick-first)


(defun djcb-mu4e-copy-message-at-point (&optional dir)
  "Copy message at point to somewhere else as <date>_<subject>.eml."
  (interactive)
  (let* ((msg (mu4e-message-at-point))
         (target (format "%s_%s.eml"
                         (format-time-string "%F" (mu4e-message-field msg :date))
                         (or (mu4e-message-field msg :subject) "No subject"))))
    (copy-file
     (mu4e-message-field msg :path)
     (format "%s/%s" (or dir (read-directory-name "Copy message to: " "~/Desktop")) target) 1)))
    ;; (format "%s/%s" "~/Desktop" target) 1)))

(global-set-key (kbd "<f5>") 'djcb-mu4e-copy-message-at-point)

;;/ mu4e ------------------------------------------------------------------------