Big response payload. Annoying to parse -- slow, or requires fiddly libraries with lots of features you aren't gonna use anyway, or both. Difficult to read. Also: Overkill.
One of my favorite lines was uttered by Philip Greenspun in 2000, back when XML was such a mindless fad that some companies were actually marketing themselves as "XML companies": "how come nobody ever talks about being a comma-separated-values company?" It was a good question then, and now that JSON and YAML are widely known and supported it is an even better question.
I could not agree more. I work daily with xml encoded apis and it's never a simple task to parse and normalize data. JSON on the other hand gives you normalized types out of the box. Very handy.
One of my favorite lines was uttered by Philip Greenspun in 2000, back when XML was such a mindless fad that some companies were actually marketing themselves as "XML companies": "how come nobody ever talks about being a comma-separated-values company?" It was a good question then, and now that JSON and YAML are widely known and supported it is an even better question.