This Repository contains the R code for an example of a shiny application which can be found: https://shiny.as.uky.edu/REDCap/. It utilizes the REDCapR package created and maintained by Will Beasley. You can find out more about REDCapR here: https://cran.r-project.org/web/packages/REDCapR/index.html.
To connect REDCap and your Shiny Application you wil need an API token from your REDCap Admin. Contact them on how to obtain this token. Once obtained, assign the token to variable and save it in an R file. You can see the api_token_testREDCapV2.R file in this repository as an example.