Service configuration for Mailcatcher Daemon (https://github.com/sj26/mailcatcher) on systemd and init.d path. Put files in /etc/systemd/system/mailcatcher.service and /etc/init.d/mailcatcher. If you choose the mailcatcher.conf option, do not need other files, put this file in /etc/init/mailcatcher.conf.

mailcatcher

#!/bin/sh
# Start/stop the mailcatcher daemon.
#
### BEGIN INIT INFO
# Provides:          mailcatcher
# Required-Start:    $local_fs $remote_fs $network $syslog $named
# Required-Stop:     $local_fs $remote_fs $network $syslog $named
# Should-Start:      $local_fs $remote_fs $network $syslog $named
# Should-Stop:       $local_fs $remote_fs $network $syslog $named
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Black hole mail server
# Description:       Catches mail and serves it through a dream.
#                    MailCatcher runs a super simple SMTP server which catches
#                    any message sent to it to display in a web interface.
### END INIT INFO

PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
DESC="mailcatcher daemon"
NAME=mailcatcher
DAEMON=/usr/sbin/mailcatcher
PIDFILE=/var/run/mailcatcherd.pid
SCRIPTNAME=/etc/init.d/"$NAME"

test -f $DAEMON || exit 0

. /lib/lsb/init-functions

case "$1" in
start)  log_daemon_msg "Starting mailcatcher" "mailcatcher"
        start_daemon -p $PIDFILE $DAEMON $EXTRA_OPTS
        log_end_msg $?
        ;;
stop)   log_daemon_msg "Stopping mailcatcher" "mailcatcher"
        killproc -p $PIDFILE $DAEMON
        RETVAL=$?
        [ $RETVAL -eq 0 ] && [ -e "$PIDFILE" ] && rm -f $PIDFILE
        log_end_msg $RETVAL
        ;;
restart) log_daemon_msg "Restarting mailcatcher" "mailcatcher"
        $0 stop
        $0 start
        ;;
status)
        status_of_proc -p $PIDFILE $DAEMON $NAME && exit 0 || exit $?
        ;;
*)      log_action_msg "Usage: /etc/init.d/mailcatcher {start|stop|status|restart}"
        exit 2
        ;;
esac
exit 0

mailcatcher.conf

description "Mailcatcher"

start on runlevel [2345]
stop on runlevel [!2345]

respawn

exec /usr/bin/env $(which mailcatcher) --foreground --http-ip=0.0.0.0

mailcatcher.service

[Unit]
Description=mailcatcher daemon
After=network.target auditd.service

[Service]
Environment=IP='0.0.0.0' SMTP_PORT='1025' HTTP_PORT='1080'
ExecStart = /usr/sbin/mailcatcher --foreground --no-quit --ip $IP --smtp-port $SMTP_PORT --http-port $HTTP_PORT
ExecStop = /bin/kill -TERM $MAINPID
KillMode=process
Type=simple

[Install]
WantedBy=multi-user.target
Alias=mailcatcherd.service