A CURIE (short for Compact URI) is an abbreviated URI expressed in CURIE syntax, and may be found in both XML and non-XML grammars. A CURIE may be considered a datatype.

An example of CURIE syntax: [isbn:0393315703]

The square brackets may be used to prevent ambiguities between CURIEs and regular URIs.

QNames (the namespace prefixes used in XML) often are used as a CURIE, and may be considered a type of CURIE. CURIEs, as defined by the W3C, will be better defined and may include checking. Unlike QNames, the part of a CURIE after the colon does not need to conform to the rules for element names.

The first W3C Working Draft of CURIE syntax was released 7 March 2007.