Open Source SMTP Relay Program

SOFTWARE Last updated August 23, 2026

Have you ever had a legacy program that some users refuse to move on from for some reason or another? Is this program so old and rubbish that it doesn’t support things like SSL or TLS so it can’t send emails to your email service because they (unlike your workplace proximity associates) are sane and refuse to allow unencrypted emails to be sent to them?

1. I’m so sorry, I know what you're going through.
2. Don’t worry, we have just the thing for you!

We attempted to write a small, lightweight SMTP Relay program in Python but kept on running into problems. In the end we discovered the project called Postfix which is designed to do just this, but is very hard to search for! This program is awesome and can receive your unencrypted emails and will forward them to any email system using all of the latest and greatest ultra modern features like TLS and port 587!

And that is it. That is all this does.

But we did our part by making it into a Docker Compose file so you can effortlessly spin it up on any server and never have to think about it again! It is confirmed working with the legacy Microsoft Access library vbSendMail.dll and sends emails through Google Workspace's (gmail) SMTP servers.

Just download the file by pressing the button below, edit the compose.yml file with your server details and then spin up the container with "docker-compose up -d".