USDA PubAg API supports the integration of apps for accessing and searching a database of agricultural publications. The database contains over 41,000 full-text journal articles by USDA staff and includes over a million citations. Access to the free web-based API requires an API key that is tied to a maximum hourly request rate of 1000 units. Permissions must be sought for higher rates of hourly requests. Released in a fully-supported and documented mode, the USDA PubAg API is flexible to either JSON or XML formats.