I have been coding mine for many years now. Fortunately it is still small enough that can be easily understood by one person. Have a look here: https://ncine.github.io/. Source: over 2 years ago

It uses my 2D framework nCine, which I recently ported to Raspberry Pi. That's why there are so many supported platforms. ;). Source: over 2 years ago

nCine is a cross-platform 2D framework written in C++11 and scriptable with Lua that can be used for games, tools, or prototypes. I have been working on it in my spare time for more than ten years and it now works out-of-the-box on the latest version or Raspberry Pi OS! Source: over 2 years ago

I created this tool for game artists a while ago, with the hope of selling it and start an independent company about game development, tools, and game technology. Unfortunately, it sold pretty much nothing so I'm back to the game industry as an employee while I decided to make it FOSS. :D It is written in C++ using my game framework nCine (https://ncine.github.io/) and ImGui, and it supports multiple platforms,... - Source: Hacker News / almost 3 years ago

Has anyone thought about using Digit's bank account? Seems like it has a lot of similar features to One/Simple. I'm definitely intrigued! https://digit.co/. Source: about 2 years ago

Also, just want to point out for anyone else who's reading that I'm not sure how well this would work for microbudgeting — e.g. gas, food, power bill, etc. — feels like that would be tedious to use with this UI. For me, I'm just setting aside rent, an emergency fund, credit card payments, and "fun money" so they're separate from my main balance. It's more like Digit than YNAB. Source: about 3 years ago