[eftpotrm]

Aside from the other commenter's point about this being a misleading comparison, you didn't need to reinvent the whole XML ecosystem from scratch, it was already there and functional. One of the big claims I've seen for JSON though is that it has array support, which XML doesn't. And which is correct as far as it goes, but also it would have been far from impossible to code up a serializer/deserializer that let you treat a collection of identically typed XML nodes as an array. Heck, for all I know it exists, it's not conceptually difficult.

[vbezhenar]

You need to distinguish between the following cases: `{}`, `{a: []}`, `{a:[1]}`, `{a:[1, 2]}`, `{a: 1}`. It is impossible to express in XML in an universal way.

[josefx]

Xsd lets you explicitly specify if you are dealing with one or more elements, no need to encode that information in the data itself. It also gives you access to concrete number types, so you don't have to rely on the implementation to actually support values like 1 and 2.

[Mikhail_Edoshin]

XML is not a data serialisation tool, it is a language tool. It creates notations abd should be used to create phrase-like structures. So if a user needs these distinctions, he makes a notation that expresses them.