By default, all results will be returned with content type {{Code|application/xml}}.
Similar to the [[REST#Content Type|REST]] interface, result serialization can be modified via [[XQuery 3.0#Serialization|XQuery 3.0 serialization parameters]]; in RESTXQ, serialization parameters may be specified in the query prolog, via annotations using the {{Code|output}} prefix, or within the query. Global parameters are overwritten by more local parameters.
===Query Prolog===