Not sure when I actually started working on the idea... But I started building it to help myself manage WordPress site for clients. I had been doing that by hand and with the help of some plugins. Then tried a few of the management options out there. I ended up using MainWP for a while, but still wasn't happy.
Once I found WP-Cli I knew that's what I wanted to use to manage the sites... But I also wanted a nice dashboard for myself and a way to track what I did for each site so I could sent clients email reports. Plus I could integrate other things as well, like UptimeRobot.