A programming language syntax that is a compatible variation of the XML 1.0 syntax. ConciseXML works to eliminate what the authors call verbosity and ambiguity in XML. The ConciseXML specifications are completely free and open, and parsers are strongly encouraged to be open source. The standard file extension for the ConciseXML syntax is .cxs. Any XML document is also a valid CXS document and a CXS document can be converted into XML.