What is the mailcatcher ?
MailCatcher runs a super simple SMTP server which catches any message sent to it to display in a web interface. Run mailcatcher, set your favourite app to deliver to smtp://127.0.0.1:1025 instead of your default SMTP server, then check out http://127.0.0.1:1080 to see the mail that's arrived so far.
docker run -p 1025:1025 -p 1080:1080 -itd nutsllc/toybox-mailcatcher
After running a container, you will go to
http://hostname:1080/ to see WEB Interface and send mail through