From the code samples it looks like it might be Ruby, but the documentation doesn’t seem to confirm or deny it either way. EDIT: I accidentally clicked on the

From the code samples it looks like it might be Ruby, but the documentation doesn’t seem to confirm or deny it either way. EDIT: I accidentally clicked on the ‘past submissions’ link on HN, and if the titles of its other submissions are to be believed, the language is actually Elixir. EDIT2: Yes, it’s probably Elixir — the front page mentions it once or twice (though not prominently; I had to search for it).