Is XML overrated? This is a question not asked lightly. It is a heavy and bloated question, much like XML itself. XML has been around since 1997. It is document based and it is extremely verbose. It requires a higher payload across the network and cannot be natively used once it arrives. The XML payload must be consumed in some fashion. None of these activities attribute to the speed of an application.

In today's world of AJAX and Flex, is XML past its prime? Does XML need to be regarded as a good idea whose time has come and gone? There are plenty of capable replacements available when using AJAX and Flex. Some examples that come to mind are JSON and AMF. Both of these formats require smaller payloads and less processing on the receiving and sending endpoints. These data interchange formats are faster and less resource intensive than XML.

XML still thrives on the strength of one key factor: its market penetration. As clunky and obtrusive as it may be, XML is still a highly-used standard for data interchange between disparate systems. Most application servers can accept XML and apply some layer of processing to the XML. EDI is a key driver to not only XML's perpetuation, but its very existence.

JSON ("JavaScript Object Notation") is a format that more and more languages are "learning" to consume. It is, as the name implies, a standard object notation. Logic can be created to consume and serialize this notation into language-specific native datatypes. The only limitation to this would be language-specific object instances which cannot be serialized and de-serialized. If more systems were to use JSON for data interchange, in lieu of XML, the payload would decrease and application performance would increase because the parsing of an XML document still outweighs the de-serialization of a JSON string.

Where does this leave the first question? Is XML overrated? There are compelling arguments on both sides of the aisle, but the answer lies in individual preference. If a developer is more comfortable with XML, it will be used. If they are more comfortable with an alternative data interchange format, that format of preference will be used.

Either way, XML will continue to exist; but its days may, indeed, be numbered.