debug.gem: Ruby's new debug functionality by Koichi Sasada This talk introduces ruby/debug: Debugging functionality for Ruby, a completely rewritten debugger for Ruby and it will be shipped with Ruby 3.1 at next Christmas. The new debugger has several advantages: Fastest debugger: Using recent introduced TracePoint features and (almost) no penalty on normal execution. Remote debugger Native VSCode (DAP) integration Easy integration with applications Thread/Ractor support And more useful features! In this talk, I'll introduce useful features of this new debugger and tips for Ruby development.