I’m a 40-year-old software developer inspired by Principles by Ray Dalio. If you haven’t yet read this great book, I strongly recommend it even if you aren’t a trader.
Another great author is Daniel Kahneman - he was awarded the 2002 Nobel Memorial Prize in Economic Sciences. It's best to start with his book "Thinking, Fast and Slow".
I became an independent software vendor back in 2004, starting with internet marketing tools, then gradually moved into the trading niche. I trade from time to time but it’s more fun for me to develop trading tools for my personal use.
There are a lot of trading-related ideas under development but the only project I’m confident to publish currently is Forex Simulator. I optimized it for manual backtesting, learning and training but it will get some automated backtesting features in the future as well.