I don't work at Discord, but Elixir seems like a perfect fit for the sort of infrastructure they build. BEAM is a marvel and there are huge success stories for

I don't work at Discord, but Elixir seems like a perfect fit for the sort of infrastructure they build. BEAM is a marvel and there are huge success stories for it when it comes to chat apps (e.g., WhatsApp). Elixir is not necessarily a fast language, though, so it's easy to see how they'd run into a need for something like Go or Rust for the occasional service where you want to push single-core performance to the limit.