There’s one nuance that needs to be made. Interactivity does not necessarily require a server behind it running code. Interactivity can be provided using embedded JavaScript, which would execute at the client-side (like plotly, highcharts, leaflet etc). So if we don’t use the word “interactivity”, but describe the interactivity explicitly, then your options become:
- Shiny: Needs a server behind it to execute R code on user input. Can implement any layout. Can run interactive code either by processing serverside (in R) or clientside (in embedded JavaScript).
- shinydashboard:Needs a server behind it to execute R code on user input. Can implement a dashboard layout. Contains some specific widgets designed to work in a dashboard layout. Can run interactive code either by processing serverside (in R) or clientside (in embedded JavaScript).
- flexdashboard: Just a document that looks like a dashboard. Also contains some specific widgets designed to work in a dashboard layout. Can only run interactive code clientside (in embedded JavaScript).
So basically, if whatever interactivity is required can be offered by an existing package (that uses htmlwidgets), then you can just use flexdashboard and you don’t need to deploy it to any Shiny server. Otherwise, you do need to deploy to a Shiny server and you should use either Shiny, or shinydashboard.