You can extend the functionality of FirstClass by creating: •       database extensions that allow the server to communicate with external databases •       client extensions that build specialized file viewers for use with the client (such as the QuickTime one in the FirstClass Plugins folder) •       client extensions that build real-time interactive applications for use with the client. To provide interfaces to database and client extensions, you must create forms that contain fields for sending data to, or receiving data from, the extensions. We provide toolkits for building server (database) and client extensions, and for building gateways to other messaging systems. These toolkits are available from the Downloads section of FirstClass Online. For database extensions, this help simply provides an overview. For full information, and for information on client and gateway toolkits, see the documentation that accompanies the toolkits. Want more functionality than is available with the toolkits? You can use FirstClass Application Services (FCAS) to add a wide variety of functions to the FirstClass client with simple BASIC coding. For information on FCAS, see the Application Services help conference.