[dividedbyzero]

It totally depends on the project, there is so much that can be a side project (even a commercial one). For CLI tools and other utilities, mostly Go. APIs and backends, Scala and Akka HTTP. For storage, usually MySQL, sometimes Kafka. For web frontends either Scala.js, Vue or vanilla JS. For infra, plain Docker or one of my k3s clusters. For IoT/electronics, Arduino and a suitable µC. For parts design and printing usually OpenSCAD and a Prusa Mini. For woodworking, a small Metabo drill, a Dremel and a set of hand tools. For illustrations and the like, an iPad Pro with Pencil and Procreate.

[ocebe]

Thank you very much for your answer, it has taught me things I didn't know