EpiGraphDB currently offers two API URLs
To switch to the development API, do
# Get default option
default_api_url <- getOptions("epigraphdb.api.url")
# Change to the development API
options(epigraphdb.api.url = "http://dev-api.epigraphdb.org")
# Verify current URL
getOption("epigraphdb.api.url")
# Switch back
options(epigraphdb.api.url = default_api_url)
NOTE: you can make this change persistent by placing the changes in .Rprofile
.