Eh, I doubt it would work well. Crystal has a couple immediate things going highly against it to start with:

• Garbage Collector: This will significantly conflict with Erlang’s GC, especially as Erlang may not give it much time to run until it decides to in some callback.

• Global Lock: This means Crystal can’t run parallel code, and the BEAM assumes it can run NIF’s in parallel, thus effectively freezing those BEAM threads until they all serially return.

If you want a native-style ruby’ish language, look at Nim, not Crystal, it would get closer to working well.

Still the main problem is garbage collector. Crystal like Go isn’t a good fit for Erlang NIFs.

It’s OK! Elixir community is so open to everything. In fact, almost half of the Elixir developers were previously Ruby developers including Jose and Chris, and the other half were Erlang developers. Those Ruby developers came to Elixir for the power of BEAM and the Erlang developers came to it for its expressiveness.

If they find something more expressive than Elixir, and more powerful and battle tested than BEAM, they’ll happily prefer it over Elixir.

In fact, DevTalk is a child forum of this forum, where we Elixir developers discuss everything, from LISP and Smalltak to OCaml and Zig, and there are some very talented members who are great at several languages.

Crystal is, of course, a very capable language. It’s statically typed, fast, and if you know Ruby, you already know Crystal. There are also some great web frameworks for Crystal like Lucky.