Besides the above query this looks great, I'm always happy to see utilities like this that can be self hosted. Not everyone is happy with a dozen external (ie saas) dependencies for their business systems!
Future plans are to put a really lightweight backend that facilitates configuration, routing, and authenticity checks (mostly SPF) during runtime but my primary goal is keeping it small. There are good things ahead once it comes out of weekend hack mode and fills out after the alpha release matures. Thank you so much for your help! Please let me know if there's anything I can do to help. I'd appreciate any feedback.
The problem is that there is already Mailgun and others providing this for free, and it's more likely that someone needing this service will prefer them, because they have less probability of shutting down the service.
This could change if you open-sourced the code and made it easier for people to run it themselves.
I wanted to make sure even if it didn't get enough traction for me to keep it up, users knew they were taken care of long term. It is 100% open source, released under the MIT License.
Please watch/star on GitHub https://github.com/withaspark/dewmail and I'd really appreciate requests, bugs, forks, and PRs!