XML is nice for this because it supports multiple schema versions, validation, and has support in just about every language. My chief complaint with json as a

XML is nice for this because it supports multiple schema versions, validation, and has support in just about every language. My chief complaint with json as a cross-language serialization/interchange format is lack of a great way to validate your format. Most of the json schema definitions i've seen require your schema to follow a certain convention, which seems backwards and wrong to me. Files can be locked if your OS supports it.