What's new in Ruby 4.0 and Bundler 4.0, a brief talk for the SF Ruby meetup in Dec 2025

(This video is only the screen, not on me). It's A nostalgic and insightful journey into what makes Ruby uniquely expressive and joyful, by exploring Ruby's most Ruby-ish features.

A look at new Ruby features in Ruby 3.x versions, with a discussion of which ones have caught on and why.

Ruby puts the Ruby in “Ruby on Rails”! It’s the Ruby language that makes Rails flexible, powerful, and with a developer-friendly API. How does Rails take advantage of Ruby’s flexibility and metaprogramming to make it so useful? And how can you take advantage of those features in your Rails app?

If you’ve learned Ruby recently, you’ve likely been told to avoid using Ruby’s metaprogramming features because they are “dangerous”. Here at RubyConf, we laugh at danger. Or at least chuckle nervously at it. Ruby’s flexibility is one of the features that makes Ruby powerful, and ignoring it limits what you can do with the language. Plus, metaprogramming is fun.