Rage Under the Hood: Breaking Rack and Embracing Fibers
Roman Samoilov
For over a decade, Roman has engineered backends across multiple languages, but Ruby has always been home. Watching company after company migrate away from Ruby not because the language failed them, but because the ecosystem hadn't kept up, he stopped debating whether Ruby was dying and built Rage instead — a Rails-compatible framework with fiber-based concurrency and a single-process runtime. Roman believes Ruby's best years aren't behind it — they just require honest conversations about what needs to change.
About
"Ruby is not dead" has become the ecosystem's favourite reassurance. It's also the wrong conversation. Ruby is alive — but companies are still leaving, and the reasons are concrete: blocking I/O by default, framework overhead that's become Ruby's reputation, and generic abstractions that prioritise backend-swappability.
Rails.cache, Active Job, the Rack interface itself — these are designed to work with everything, which means they're optimised for nothing.
This talk introduces Rage, a framework that takes the opposite approach: every layer is purpose-built for a fiber-based, single-process runtime. No generic adapters but tailored solutions for a specific architecture. Rage challenges the status quo by coupling directly with the web server and leveraging the Fiber Scheduler to achieve asynchronous I/O that feels synchronous to write. In this talk, we'll open up the framework and look at the decisions inside:
- The "Synchronous Illusion" — how Rage lets developers write linear Ruby that executes asynchronously, with no callbacks and no new syntax.
- "Promise.all" style concurrency using Ruby Fibers — and the scheduler mechanics that make it possible.
- What we learned by replacing ActiveRecord's connection pool — and how it unlocked a 2.6x throughput gain in CPU-bound workloads.
- Real-world load tests comparing Rage against standard Rails setups under sustained heavy traffic.
This talk is for anyone who believes Ruby's best days aren't behind it — but only if we're willing to rethink the foundations.
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