- a graphical user interface ( GUI ) through which a user can interact with the system using a web browser , or
- a web service through which the system makes data or functions available to other systems.
Examples of web interfaces are the Google API, which software can use to access functions of the search engine using SOAP and WSDL , or the integrated web server of a DSL router , which a user can use to make changes to the device configuration.
The web interface as a GUI has the advantage of being platform -independent, since a web browser is available for almost every network-compatible operating system and is usually already supplied, so that no additional software has to be installed to use a web interface . The disadvantage here is, among other things, the limited possibilities that a GUI consisting of HTML pages brings with it. In the future, however, WebSocket , HTML5 , CSS3 , jQuery and jQuery UI can bring significant improvements.
The use of a web service for data exchange between two systems can be advantageous, since the data transport via HTTP is established independently of the programming language and across platforms and is usually also permitted through firewalls . The additional administrative effort (English overhead ) on the data to be transmitted and the higher computational effort when creating and analyzing the XML data structures may have a disadvantage here .
By definition, the role of an interface only involves passing on information. However, if processing is already taking place here instead of leaving this to the system behind it, it is a web application .