A few weeks ago, I had about 100 config files (tomcat context.xml) which all needed fixes for common misconfigurations - if they had the misconfigurations in t

A few weeks ago, I had about 100 config files (tomcat context.xml) which all needed fixes for common misconfigurations - if they had the misconfigurations in the first place The kind of problem that is just a little bit too hard for search and replace. It was really easy with xslt. The result had all comments preserved. I choose to reformat the files, but keeping whitespace was an option too. Now tell me if you can do that with json,yaml,toml. Most parses simply forget about the comments to begin with. In the same way, if we receive a data transfer in XML and there is a schema, simple validation catches a lot of problems quickly. You'd be surprised how many times a company gives you a schema and then sends you xml which doesn't validate. In JSON, you have to write a program to get even basic validation. Don't get me wrong: XML has problems, some inherited from html/sgml (entities!), and even more after serious abuse by consultants, archicture astronauts and enterprise vendors (SOAP! namespace overuse! 10 XML parsers in 1 app!). But it was also miles better than what came before and I feel the XML hatred pendulum has swung too far. Today, JSON is in vogue, and I've seen enough IT to not swim against the tide. It is a reasonable solution for problems caused by XML abuse. Besides, there is value in going with the majority,even if it only fixes 80% of your problem. But I can only weep for the miserable date, numeric and comment support, and their endless stream of incompatible workarounds. For your parameter example: You can't both strictly validate and have full freedom at the same time. Something has to give a bit. Some less horrible alternatives I've seen: <parameter name="X" value="Y"/> <subsystem name1="value1" name2=value2 ... /> , add newline for each attribute <name>value</name>