From DHH's long-winded keynote at Rails World 2026. He was bragging that Hey's backend is so efficient because it's written in Rust (which he hates and refuses to read).
Also: they assemble their own system Backend; Artix is a different distro from arch, because it uses a different init system (openrc instead of systemd + other choices), but manjaro isn't, it's just arch with a shitty toolkit (pamac).