Techniques for transferring a serialized image of data for an XML construct includes selecting a first format from multiple different XML serialization formats that represent, in a database system, data for XML constructs as a series of data units, such as a series of bytes representing characters, or a series of bits, bytes or octets representing binary values. A message is generated that includes a payload and a payload type field. The payload includes particular serialized data that represents particular data for a particular XML construct in the first format. The type field includes data that indicates the first format. The message is sent from a sending component of the database system to a different receiving component of the database system. These techniques allow the format selection to be based on characteristics of the sending or receiving components to make better use of the resources available to the two components.