For golang developers you can tell them that you have the same lightweight concurrency without any deadlocks or other low-level problems that golang concurrency has at its API level.

You can always show them some intricate pattern matches (and their equivalent in other languages), don’t forget about binary pattern match, a killer feature in itself (also a good example of some binary parser section in elixir vs other languages might be welcome).

For rails developer, there is phoenix, you could show them some shiny new things that they don’t have (for example how heex can validate html at compile-time).

Another killer feature is runtime interaction and observability. This video by @sasajuric is an absolutely great demonstration of that.

I would skip fault-tolerance (maybe just mention it and if there are questions you can expand on that), as for people that never used erlang VM this is an unknown concept that needs a separate talk in itself. If you could come with a simple but effective demo to showcase that for a real-life problem, it might be well worth to display that too.

Distribution, livebook, nx, bumblebee are also a great topic. These things are beyond what those languages can achieve, however you could showcase them for example how easy is to connect to a remote machine and run a computational task with livebook.

Watch the video @D4no0 linked by Saša Juric (The Soul of Erlang and Elixir) for shock value.

You mentioned the community and I’m taking that as not just Elixir itself, so I’ll answer it within this context:

• Ecto, the sql part
• Ecto, the non-sql part (@gregvaughn’s talk is one of my favorites )
• Pattern Matching
• Liveviews that update themselves periodically
• GenServers that update themselves periodicaly

That’s what I’d try to squeeze in a work intro session.