Half a year back or so I built a mini SaaS product that failed, now I'm in the process of open sourcing it so that everybody can freely host it for themselves. Here's the project homepage https://magiclogin.net, it was/is transactional e-mails and e-mail authentication as a service.

Getting it ready for open sourcing is a lot more work than I anticipated, I don't want to just dump it in a Github repo and have nobody be able to actually use it, so I'm making deployment easier and writing docs on how to run it yourself.

I didn't build the project to make money necessarily, it was mostly a learning project. That doesn't mean that I didn't hope it would be at least moderately succesful financially. But it was a case of "build and they won't come" and my other projects took off much more so I couldn't justify trying to market/pivot it. The final nail in the coffin came when I received a cease and desist letter because apparently a vc-funded auth provider trademarked the term "Magic Login".. So yeah..