Reactive Log Visualizer
Provides an interactive browser-based tool for visualizing reactive dependencies and execution in your application.
To use the reactive log visualizer, start with a fresh R session and
run the command
options(shiny.reactlog=TRUE); then launch your
application in the usual way (e.g. using
any time you can hit Ctrl+F3 (or for Mac users, Command+F3) in your
web browser to launch the reactive log visualization.
The reactive log visualization only includes reactive activity up until the time the report was loaded. If you want to see more recent activity, refresh the browser.
Note that Shiny does not distinguish between reactive dependencies that "belong" to one Shiny user session versus another, so the visualization will include all reactive activity that has taken place in the process, not just for a particular application or session.
As an alternative to pressing Ctrl/Command+F3--for example, if you
are using reactives outside of the context of a Shiny
application--you can run the
showReactLog function, which will
generate the reactive log visualization as a static HTML file and
launch it in your default browser. In this case, refreshing your
browser will not load new activity into the report; you will need to
For security and performance reasons, do not enable
shiny.reactlog in production environments. When the option is
enabled, it's possible for any user of your app to see at least some
of the source code of your reactive expressions and observers.