The docs on cl-smtp are a little, um, terse, so I figured I’d post a few snippets for google to find: Sending html email with cl-smtp: (cl-smtp:send-email +mail-server+ “from-email@example.com” “to-email@example.com” “Subject” “<html><body> <p> Shiny <strong>h</strong><em>t</em><small>m</small>l. </p> <p> </body></html>” :extra-headers ‘((“Content-type” “text/html; charset=\”iso-8859-1\””))) Sending attachments with cl-smtp: (cl-smtp:send-email +mail-server+ “from-email@example.com” “to-email@example.com” “Subject” “see attachement” :attachments ‘(“/path/to/attachment”)) […]