What if trying a Ruby gem was as easy as opening a web page – no local setup, no "bundle install," no version headaches? TutorialKit.rb enables interactive, runnable tutorials for Ruby gems directly in the browser by combining Ruby on WebAssembly with an in-browser development runtime.

This talk presents the grant-funded evolution of the project: TutorialKit.rb was awarded a Ruby Association Grant in 2025, and the work from that grant is the core of what I'll share at RubyKaigi 2026.

First of all I'll showcase building an example tutorial using the framework. . RubyKaigi is a technical conference, so then we'll go beyond the demo and focus on the engineering: the architecture that wires Browser → WebContainer → Ruby WASM, the Ruby ⇄ WebContainer bridge, and the build/distribution pipeline that makes a full-featured development workflow possible inside the browser.