1. A method comprising: establishing, on a feed adapter, at least one configuration policy of a plurality of configuration policies and a message model, wherein said establishing at least one configuration policy of the plurality of configuration policies and the message model on the feed adapter comprises the feed adapter receiving, from a stream administration server, at least one of a first configuration policy of the plurality of configuration policies and the message model; receiving, at the feed adapter, an indication of a second configuration policy of the plurality of configuration policies; selecting, on the feed adapter, the second configuration policy of the plurality of configuration policies based, at least in part, on said receiving the indication of the second configuration policy of the plurality of configuration policies, wherein the second configuration policy of the plurality of configuration policies specifies a conversion rule from an input message format to an output message format using at least one conversion function of a plurality of conversion functions, wherein the conversion rule specifies types of arguments that the at least one conversion function receives and returns; receiving, in the feed adapter, an application message having the input message format; converting, by the feed adapter, the application message having the input message format to an application message having the output message format according to the conversion rule specified by the second configuration policy of the plurality of configuration policies.