The i4 Frontend Environment (FE) offers a GUI-Editor to allow i4 App developers the implementation of end-user interfaces for their solutions. It will be accessible from within the Studio as a plain browser consuming external microservices. These services provide large ranges of visual templates implemented in HTML5 + CSS3.

Developers can combine these templates within the GUI editor to achieve enclosed i4 App visualisations at the end. The templates can stand for themselves (eg customized GUI elements) or contain additional behaviour and logic (eg registration forms or error representation). i4 App developers thus will have a high degree of flexibility and power as there are barely any restrictions in merging templates.

The FE will still develop an abstraction layer concept, subordinating the entities into abstraction levels. This strategy will produce additional guidance for the developer and speed up the process of rapid prototyping. The editor also allows external configuration like translations for internationalisation, as well as internal, individual configurations for each template itself. The module is subdivided in lower-level modules:

• The Client-Module is a single HTML file, processing user inputs and forwarding them to the mircoservices module, where necessary calculations for representing i4 Apps take place.
• The Server-Module consists out of multiple mircoservices working together, which listen to user inputs and transform them into clickable prototypes of a i4 App.