The FHIR API

Abstract

, based on established web standards and modern information exchange that has been extended to create a full interoperability solution for health care. The use of common and widespread technologies lowers the barriers to entry for using the standard by making it easier and faster to implement while also opening up development to individuals who do not have health care expertise. What is an API? An API is an entry point, or "interface," that allows a computer program or system to access the features and data of a different program or system. This entry point defines how data must be formatted and the types of interactions supported, such as how data can be searched. To be successfully exchanged and ready for an operation, data must be formatted in the same way. For example, a data field to be used in calculations cannot accept both "1" and "one" as entries, as they cannot be interpreted the same way. APIs can be simple, with rigid definitions of data structure, or complex, with different data structures for a wide array of interactions. The FHIR API mainly involves the access and exchange of data. Many modern applications, both desktop and mobile, use APIs to retrieve, store, and update data. Many applications run on a mobile device or web browser use the information exchange standard REST (Representational State Transfer) as the basis for their APIs. REST is a method of exchanging information using the World Wide Web standard transfer protocol HTTP 1 , the underlying internet standard that forms the basis for all website data exchange. "Http" can be seen at the beginning of every webpage's web address, such as "http://www.healthit.gov". REST means that each request from any client and response from the server contains all the information necessary to service the request. The exchange of data using REST is termed a "RESTful" exchange. A RESTful Resource creates a way to access data through a specific endpoint, using specific structures and formats. More strictly defined structures and formats enable more-precise data exchange. In FHIR, which uses such strictly defined structures, a system can target and retrieve just a single data element rather than receive a document containing a patient's full record.