API provides access to a specific system, application or service. The interface itself is most frequently performed through a set of applications or a source code which both use various programming languages, standards and protocols. Knowing a specific API, the programmer can easily utilize its advanced features using standardized commands and instructions. In web applications, API is used, for example, to gain specific information without providing access to the database. Interface examples: DirectX, ODBC, OpenGL, Windows API. Common standards: XML, SOAP, WSDL.