Sets the API key used to authenticate requests to the FRED API. The key
persists for the current R session. Alternatively, set the
FRED_API_KEY environment variable in your .Renviron file.
Details
Register for a free API key at https://fredaccount.stlouisfed.org/apikeys.
See also
Other configuration:
clear_cache(),
fred_cache_info(),
fred_get_key(),
fred_request()