An RFC 851 compliant implementation of SMTP written in golang
The package is not available in any repositories at the moment, so you will have to build from source.
After running go install, you can run it to see the available options.
smtpd --help
This is not production ready. It is a compliant implementation of RFC 851 that is meant to be used for debugging purposes. I am also using this project as a learning tool and reference for others wanting to learn how to implement common protocols. As of now, I plan on making a tool similar to mailcatcher.