1. A computer-implemented method, the method comprising, generating an encoding specification for a unique virtual item, wherein one or more components of the encoding specification influence appearance properties of the unique virtual item, said generating comprises deriving a first set of the one or more components from a plurality of items of personalization information, the plurality of items of the personalization information describe a rule set selection, and the plurality of items of the personalization information comprise items describing at least one or more transaction parties identified in a request for the unique virtual item or one or more configurable feature specifications indicating requested properties of the unique virtual item; creating from the encoding specification one or more item characteristics for the unique virtual item, wherein the creating from the encoding specification the one or more item characteristics for the unique virtual item further comprises selecting based on the one or more components the one or more item characteristics set from a set of options provided by a rule set, and the one or more item characteristics describe a unique feature set for the unique virtual item in terms customized for a type of a rendering client selected from a plurality of rendering client types to render the unique virtual item; and sending the one or more item characteristics to the rendering client.