DHH Went Completely Off the Rails: How the Creator of Ruby on Rails Embraced Vibe-Coded Rust and Set His Community on Fire

David Heinemeier Hansson spent twenty years preaching the beauty of Ruby and the elegance of hand-crafted code. In one keynote, he torched it all.

The Rails World 2026 conference should have been a celebration. For nearly two decades, Ruby on Rails creator David Heinemeier Hansson—DHH to the developer world—has taken the stage at his community's flagship event to unveil a shiny new Rails version and remind everyone why Ruby is the most beautiful language ever written. This year, he used the platform to announce that his company is abandoning it.

The keynote began with a seemingly tedious preamble about painting and photography. Then DHH lit the fuse: the next version of HEY, 37signals' flagship email client, will not be built on Ruby on Rails. The frontend will be native applications across every major OS. The backend will be written in Rust. Neither the frontend nor the backend would touch Rails.

The room went silent. The X app notifications reportedly overloaded as the developer community erupted.

"The Ugliest Programming Language of the Past 40 Years"—And That's the Point

DHH has never been shy about his contempt for Rust. At the same conference, he called it "the ugliest programming language invented in the past 40 years" and said that reading Rust code feels "like someone poured acid into my eyes". He has spent years mocking Rust in talks and interviews, most recently on the Lex Fridman podcast, while using code from Basecamp and HEY to demonstrate Ruby's superiority.

But here's the twist that defines his entire new philosophy: he doesn't care anymore.

"If I never have to look at the code, and just enjoy applications that are 30 or even 100 times faster, compile to tiny executables, and start in under a millisecond—then I love Rust!" he declared on stage. "The Agent likes Rust. That forms a perfect division of labor: I tell it what to do, it writes it in Rust, and I never have to look at that code. I really like this approach".

This is the core of DHH's new religion. Rust is a terrible language for humans. It is a wonderful language for LLMs. And since humans are no longer writing the code, the human experience of the language is irrelevant. "Writing code by hand is now an exceptional state," he told the audience, revealing that he personally stopped hand-writing code about four months prior. At 37signals, "all programmers now only work with agents". When he polled the room of roughly a thousand Rails developers, asking who still programmed manually, only five hands went up.

To underscore the point, DHH shared that only about 3% of his code output in 2026 was Ruby—down from roughly half his work over the previous two decades. In August alone, he reported writing around 150,000 lines of code, mostly Rust generated by LLMs, compared to a pre-LLM average of about 30,000 lines per year. He did not personally review much of that generated code.

The Benchmark That Broke the Camel's Back

If the keynote was a bomb, the follow-up was the explosion. Two weeks later, DHH posted a benchmark comparing the performance of his company's Campfire group chat app rewritten by AI agents in Elixir, Go, and Rust against the original Ruby on Rails implementation.

The numbers were staggering. In one test serving a "room page," the Rust version handled 36,260 requests per second. Ruby on Rails managed a paltry 241. Elixir delivered 722, and Go—the runner-up—managed only 3,860. That's a roughly 150-fold difference between Rust and Rails. DHH wrote: "Yes, Ruby is the slowest. In the past I didn't care, because it bought enormous productivity and development joy. But what if you no longer read the code?"

The performance gains extend beyond benchmarks. DHH claimed that moving HEY's backend from Ruby to Rust could cut CPU usage by approximately 99% and memory usage by about 95%. The rewritten HEY backend reportedly uses so few resources that a single Raspberry Pi could handle peak traffic, with ten servers retained only for redundancy. These claims, if accurate, represent a transformation in efficiency that would reshape the economics of running a software business.

But the developer community was not impressed. They were furious.

The Benchmark Was Rigged—And Everyone Knew It

It didn't take long for developers to dig into the repositories and discover that the comparison was far from fair. Elixir creator José Valim examined the code and found that the Rust version had undergone 398 optimization commits, while the Elixir and Go versions each received only three. The Rust implementation had been iteratively tuned and refined over numerous sessions, while the other languages' versions essentially remained at their first-pass AI output.

One observer put it bluntly: "One is a Rust-written native HTTP parser, the other is Ruby with a Rack middleware library. How is that even the same race?"

The criticisms cut deeper than mere fairness. Critics noted that the Rust version didn't maintain 100% backward compatibility—it dropped CSRF tokens to make caching easier. Vague prompts led to inconsistent architectural decisions across language versions, with each implementation making different tradeoffs. A reproducible benchmark conducted independently across seven languages, four LLM configurations, and 112 implementation attempts found that no language ranking held up. Under load, the four stacks tied on throughput.

The episode revealed a fundamental problem with DHH's "vibe coding" philosophy: when you don't read the code and don't understand the optimizations being applied, you can't tell the difference between a legitimate performance comparison and an elaborate confirmation bias.

"He Has Lost His Mind"

The Rails community's reaction ranged from grief to open revolt. On the Ruby Users Forum, one developer wrote: "I haven't watched it, but the buzz on the street is that DHH has lost his mind. He went from advocating the majestic monolith in Ruby and Rails to microservices in Rust and decided this was the best platform to not talk about Rails and instead announce that his company is now building in Rust".

Another community member captured the sense of betrayal: "DHH has abandoned those values in favor of LLM-written slop Rust code that 'you never, ever, EVER have to look at it yourself.' I hope that Rails moves on from DHH and continues to be a place where you write code to bask in the warm glow of beauty. Because that's what made Rails distinct".

The sting was particularly sharp because this was a Rails conference. As one observer noted: "It's just wild that the keynote for RUBY ON RAILS was about WRITING SOFTWARE IN RUST. I know Rails is DHH and DHH is AI-pilled, but there wasn't even really anything about how they're making Rails better for agents". DHH announced his company was moving off Rails to Rust at the flagship Rails event, with no new Rails features discussed.

The Kodak Moment

DHH framed his shift as a "Brownie moment"—a reference to Kodak's Brownie camera, which democratized photography and made professional portrait painters obsolete. In his telling, AI is the Brownie of software development, and hand-written code is the portrait painting that's about to disappear.

"We are no longer attached to this piece of code that has been produced by prompts because, I mean, we didn't write it," he said on the REWORK podcast. "There's not a human on the other side. If you tell the AI to—well, you don't tell the AI; you just start a new session and boom, amnesia. They've completely forgotten that they spent a lot of expensive tokens producing this stuff, and they're not offended".

But the Basecamp 5 experience suggests the transition isn't as smooth as DHH's keynote implied. An early attempt to let designers vibe-code features left the architecture looking like "Swiss cheese," and the company reverted to manual coding. DHH frames this as a lesson learned, not a warning sign.

What This Means for the Rails Community

The irony is thick. Ruby on Rails was built on the premise that developer happiness and productivity matter more than raw performance. DHH spent two decades arguing that Rails' conventions-over-configuration philosophy made it the best choice for small teams building ambitious web applications, even if Ruby wasn't the fastest language. That was the deal: you traded some performance for enormous gains in development speed and joy.

Now DHH is saying the deal has changed. If AI writes the code and you never read it, the productivity argument evaporates. What remains is performance—and Rust wins that contest by a mile. The benchmark controversy doesn't change the underlying math: even a fairly tuned Ruby implementation cannot compete with even a moderately tuned Rust one on raw throughput.

But the community is wrestling with a deeper question: if the creator of Rails no longer believes in Rails, what does that mean for everyone else? DHH's answer seems to be that they should follow him into the vibes—let AI write Rust, never look at it, and enjoy the speed. His critics argue that this is a recipe for unmaintainable systems, hidden bugs, and a generation of developers who can't reason about their own code.

The 398 commits it took to optimize the Rust version reveal the uncomfortable truth at the heart of the vibe-coding dream. Someone—or something—has to do the work. The optimizations didn't emerge from a single prompt. They required iterative feedback, measurement, and refinement. DHH may not have written the code, but the process that produced the benchmark numbers was anything but effortless.

Whether DHH's vision represents the future of software or the most dramatic self-immolation in developer community history, one thing is certain: the Rails community will never see its founder the same way again. The man who built a framework on the promise that programming could be beautiful has declared that beauty no longer matters. All that's left is the vibe.

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