A codec plug-in needs to be structured as a dynamic shared library. In order for the IAF to be able to load and use it, it must comply with Apama's codec plug-in development specification. This describes the overall format of a codec plug-in and the C/C++ functions it needs to implement so that its functionality is accessible by the IAF. The Specification also provides a mechanism for startup and configuration parameters to be passed to the plug-in from the IAF's configuration file.

Property names and values used by codec plug-ins must be in UTF-8 format.

A codec plug-in implementation must include the C header file EventCodec.h. This file can be found in the include directory. As a codec also needs to communicate both with a transport layer plug-in (or event transport) and with the Semantic Mapper, EventTransport.h and SemanticMapper.h also need to be included.