It’s time to leave XML behind in APIs. It’s verbose, it’s hard to parse, it’s hard to read, its data model isn’t compatible with how most programming languages model data and its extendibility advantages are irrelevant when your output representation’s primary needs are serialization from an internal representation.
I’m not going to put much effort into explaining the above breathful as it looks like others (YouTube,Twitter & Box) have already starting the XML exodus.
I’ll just leave you the following Google Trends chart (XML API vs JSON API) as food for thought:
However, if your customer base consists of a large number of enterprise customers, you may find yourself having to support XML anyway.