Java (4+ years)
SQL RDBMS such as SQL Server, MySQL, PostgreSQL (5+ years)
Golang (3+ years)
C# (2+ years)
Managing Linux systems running Debian, Ubuntu and Arch (4+ years)
While I don't prefer frontend, I have interacted with these frontend frameworks in projects/production software in the past
JavaFX, Laravel, Svelte & Vue
For backend, I have used the following software to build and host various servers and websites
Gin, gorilla/websocket, Caddy & Docker
RISC-V emulator in C#, for which I want to write some programs in RISC-V assembly
Work-in-progress internet Go (board game) server in Go (programming language) using WebSockets
Yes, I've handwritten this website. You can learn more about it and how it works by reading the source. Or you can read the blog article.