St. Louis Fed Web Services: FRED® API
fred.stlouisfed.org/docs/api/fred#APIThe FRED® API is a web service that allows developers to write programs and build applications that retrieve economic data
from the FRED® and ALFRED® websites
hosted by the Economic Research Division of the Federal Reserve Bank of St. Louis.
Requests can be customized according to data source, release, category, series, and other preferences.