Note that you linked to the 0.1.1 version of the gleam_otp documentation. The latest version resides at https://hexdocs.pm/gleam_otp/index.html and both gleam_erlang and gleam_otp have hit 1.0.0 already. It doesn't contain every feature yet (like dynamic supervisors) but it's usable (and I've rolled my own dynamic supervisor in the meantime).