The IBM® Forms Server – API provides low level access to XFDL forms in Java™, C, and COM.
Using the API, you can develop applications that process XFDL forms, including XForms data models within XFDL forms. You can create and manage applications that analyze, route, validate, and create electronic forms.
The API also contains the Function Call Interface (FCI) library. Using the FCI, you can extend the capabilities of your forms by adding custom XFDL functions that are available to forms designers for use at run time.