Enjoy Ruby Programming in IDE and TypeProf by Yusuke Endoh The rich development experience in integrated development environments (IDEs), including on-the-fly error reporting, refactoring feature, completion, etc., has become increasingly important. To achieve this, many programing languages are incorporating annotations such as type hinting. However, is such IDE features infeasible without annotations? We are challenging ourselves to achieve modern development experience with non-type-annotated Ruby programs by using TypeProf, which is a type analysis tool bundled in Ruby 3.0. In this talk, we demonstrate our prototype, and present its roadmap.