Application Programming Interface (API)

API is the abbreviation for application programming interface, also known as programming interface or application programming interface. It enables communication between parts of an application or between two different applications by specifying exactly how these applications can communicate with each other. Nowadays APIs are indispensable for good and fast functioning web applications where data has to be queried or transferred in a certain form.


The advantage of an API is that different functions do not run in one program, but are modularly separated from each other. This makes the actual applications leaner and faster.


In this way, an application that displays the current weather on a website for example does not require a large program part that collects and calculates weather data, but instead requests this information via an interface from a database that is provided and updated by one of the large weather services.


Other examples of frequently used APIs:


  • Travel API: Hotels, tour operators or airlines pass on information on current room occupancy, prices and connections to a service provider. Using an API, prices and available hotel rooms, flights, etc. can then be queried on the travel portals in real time and, conversely, bookings can be transmitted to the hotels.
  • Newsletter API: The newsletter API specifies how a form on a website can communicate with an email service provider (ESP) to transmit the correct parameters and values as well as success or error messages.
  • IP Geolocation API: Based on the IP, the current location of the user is retrieved.
  • Sports API: Using such an interface, sports results can be queried live.


Programming interfaces are used in a wide variety of cases. Without APIs, many web services that we naturally use today (such as hotel bookings via price comparison portals) would not be possible.

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