An (>application-programming interface (API)) is a set of commands for accessing an application or system. A software company publishes its API so that other software developers can design products that are powered by its systems and services.
An API is a software-to-software interface, not a user interface. With APIs, applications talk to each other without any user knowledge or intervention. For instance, when you buy movie tickets online and enter your credit card information, the movie ticket website uses an API to send your credit card information to a remote application that verifies whether your information is correct. Once payment is confirmed, the remote application sends a response back to the movie ticket website saying it’s approved to issue the tickets.
As a user, you only see one interface—the movie ticket website. However, behind the scenes applications are working together, sharing select pieces of information, using APIs. This type of integration is called seamless, since the user never notices when software functions are handed from one application to another. [source: TConsult, Inc.]
In the world of medical imaging, APIs are often used to integrate image management systems, such as Picture Archiving Communication Systems (PACS), directly into EMR systems. This is referred to by many as “Image Enabling the EMR.”
This is a more seamless and robust method than the traditional way of sending just the results of the radiology report via HL7 to the EMR—which then could offer only a blob of text viewed in the EMR. With an API, the user gets a link to the actual images and report inserted directly into a patient’s record in the EMR.
Absent an API interface, EMR workflows might require users to collapse the EMR window, open the PACS window, enter a username/password and manually search for the patient’s exam(s). An API allows single-click access to the same information via a link inserted into the patient’s record in the EMR. The API negotiates the security in the background and retrieves both the images and report for that patient. This enables the requested information to be presented in a single view that is a very powerful combination of text and images for the user.