4YTech (formerly at 4ytech.com, which I seem to have registered in 2012) was probably one of my earliest forays into full stack web development. I'm not sure exactly what it was supposed to be, but presumably 4YTech was going to act as an umbrella organisation for all my other projects. 4Y refers the initials of myself and my three younger siblings (all our names start with a Y) and was probably inspired after the name of my father's business (3Y; founded before my sister was born).
I remember mainlining PHP tutorials and adding onto those until I built a pretty solid user accounts system. I learned a lot about the classic attack surfaces (XSS, SQL injection, etc) and how to mitigate those, as well as salting and hashing passwords the right way. This account system wasn't actually useful for anything, you just got a profile, but eventually I used it for Metaplains.
Over the years, I also ported that logic over and over again to different languages and frameworks, including the NodeJS + Express + MongoDB-based account system that Krew uses, which is probably the most advanced iteration of this code with humble beginnings (all available on GitHub).
I also remember that at the time I wasn't quite at the point where I could spin up everything I needed myself, so I used a managed web host, called Just Host, that my friend from uni, Khalid Khattak, recommended. It had MySQL, phpMyAdmin, and all the necessary dashboards working out of the box. I think all I was really doing was syncing my files over with FileZilla, an FTP client. I very quickly learned how to do everything myself though, to save money!