The FGL Platform was designed to be a single all-inclusive platform for the creation and execution of complex standalone and web-based applications. And, while it has numerous built-in functionality, it was also designed to be readily extensible.

The easiest way to extend FGL is by creating an FGL binary library. FGL libraries can contain data, functions, and class definitions and are bound together using the FGL Librarian.

The platform can also be extended by virtually any language capable of generating a DLL, ActiveX control, COM object, as well as .NET or Java assembly via the FGL 3rd-party interface (TPI). This interface allows enhancements to the system using thousands of industry-standard components or add-ins created by individual developers without any change or modification. FGL utilizes a registration file to identify the exported components of the add-in and define any required interaction. This may include function definition, data typing, parameter passing (including variable parameters), and ownership and responsibility of memory and other resources.

Additionally, the FGL environment includes a comprehensive API that provides direct manipulation of the internal environment and access to variables, class definitions, and managed memory.