DHH has agents rewrite Campfire in Rust: 36,260 req/s vs Ruby's 244, a 150x gap
sujingshen · x · 2026-10-06
Rails creator DHH had agents rewrite his Campfire chat app in Elixir, Go, and Rust. Same room page requests/sec: Ruby 244, Elixir 722, Go 3860, Rust 36260 — a 150x gap. His decades-long pitch was "Ruby is slow but joyful to write; programmer time beats server cost," then he asked: "but what if you no longer read the code?"
- The poster argues that when agents write and verify code, human-side joy shrinks while machine-side runtime cost stays, so language choice will shift from developer ergonomics to runtime economics.
- Caveats: speed isn't everything (Rust compile times hurt); commenters note the 10x Go-vs-Rust gap looks like unoptimized versions; on write operations like sending messages the Ruby-Rust gap narrows to 27x.
- Takeaway: the "slower but humans are happy" trade-off assumes people live in the code daily — an assumption agents are eroding.
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