BEAM based languages lack "good" debuggers, because they historically depend on tracing instead of debuggers. I recently wrote a blogpost about the tracing landscape in Elixir. https://www.erlang-solutions.com/blog/a-guide-to-tracing-in-... But the main reason is that BEAM languages are mainly used for concurrent computing which is a very difficult problem to debug with classical debuggers. I know it is not a mainstream way to "debug" but a very useful one once one learns it.