You can obtain data from an Internet source or from in-house applications that can restrict access to data by using a JSON or XML interface. Both use the HTTP protocol that includes a base address to establish a connection, conduct authentication, and then query for the data.
JSON
JSON (Javascript Object Notation) is a lightweight data-interchange format. JSON interfaces have an HTTP Base Address for the data set and an API key. The Base Address can be parameterized. The Current Value, Trend Data, and Historical Value each require a Request URI, which specifies the date, order of returned values, number of values and the data set, a Result Base Path, Value Field, and Timestamp Field.
XML
XML data sources use JSON interfaces but with an XML type instead of JSON type in the Result Data Format.