An API or Application Programming Interface is an application programming interface.
In other words, an API allows you to automate actions that you would have performed manually by integrating « API calls » directly into your scripts or business softwares.
Interconnection with an API requires computer development skills and can be developed in a majority of programming languages.
The most commonly used languages for their ease and speed of execution are Python, Perl and PHP. However, it is also possible to use more specific languages such as Powershell.