A method, system and computer program product for decreasing a volume of data transmitted from a server to a client device in a data processing network, the server processing a received request for a resource from the client device, the processed requested resource comprising data embedded in a file of elements, the elements defining a format of the data. The method comprises the steps of: intercepting the processed requested resource; a first parsing step, parsing the processed requested resource to identify at least two occurrences of a formatting element; associating an identifier with the identified formatting element; a second parsing step, parsing the processed requested resource to extract each of the data elements associated with the identified formatting element; and constructing a code set comprising the identifier and each of the extracted data elements associated with the identifier.