A system, method and computer program product for communicating Web-Services (WS) messages. First there is allocated an identical amount of a cache history storage at each sender and receiver device for storing a history of communicated WS message strings. At the sender, there is generated an intermediate data representations of each message being built, the corresponding message string stored in the cache history storage. The message is communicated as a serialized data string according to the built data representation. For each subsequent message to be communicated, the method comprises identifying identical portions in intermediate data representations of a current message being built and replacing each identified portion in message strings with a reference indicator to a location in the cache history storage corresponding to an identical character string portion associated with a prior message that has been communicated. At the receiver device, the references are identified in received message strings and one or more intermediate data representations locally stored at the receiver device are substituted in the message to complete a build of the received message.