reactlog

reactlog is a debugging tool that visualizes the reactive dependency graph of Shiny applications. It logs reactive interactions during app execution and displays them as an interactive directed graph, helping developers understand and debug Shiny’s reactive behavior.

The tool identifies common reactivity issues like unused reactive elements, over-utilized computations, unexpected dependencies, and invalidation problems. It provides interactive features including time-travel debugging through reactive history, family tree highlighting and filtering, and element search. This visibility into Shiny’s reactive system helps developers optimize performance and fix bugs that would be difficult to diagnose from code inspection alone.