AMF is a binary format based loosely on the Simple Object Access Protocol (SOAP). It is used primarily to exchange data between an Adobe Flash application and a database, using a Remote Procedure Call. Each AMF message contains a body which holds the error or response, which will be expressed as an ActionScript Object.
Adobe Systems published the AMF binary data protocol specification on December 13, 2007 and announced that it will support the developer community to make this protocol available for every major server platform.
Zend_Amf provides Action Message Format (AMF3) support for the Zend Framework that is compatible with the Flash Player 9 and above. The Adobe Integrated Runtime (AIR) and Flash Player uses AMF to communicate between an application and a remote server. AMF encodes remote procedure calls (RPC) into a compact binary representation that can be transferred over HTTP/HTTPS protocol. Objects and data values are serialized into this binary format, which increases performance as the AMF serialization is a highly optimized procedure in the Flash Player. Zend_Amf will act as an AMF gateway to the Zend Framework by exposing through introspection custom class objects and functions that will respond as callbacks through the Zend_Amf gateway.