Tutorialkit.rb: interactive Ruby tutorials entirely in the browser—Martian Chronicles, Evil Martians’ team blog

TutorialKit.rb has reached release candidate stage, enabling interactive Ruby and Rails tutorials that run entirely in the browser using WebAssembly and WebContainers. Key features include a scaffolding CLI (`npx create-tutorialkit-rb`), Claude Code skills for agent-friendly development, deployment pipelines for Netlify and Fly.io, and HTTP support via a JS bridge that routes Ruby's Net::HTTP through WebContainer's Node.js fetch. The post details three dependency-packing strategies (monolithic, tarball, deferred packing), with deferred packing emerging as the optimal approach: ~2-5s boot time, seconds to rebuild, and ~77MB binary size. A complete Action Policy tutorial is live as a real-world showcase. Future work includes lighter template variants, WASI Preview 2 migration, and eventually removing the WebContainers dependency entirely.