Encoding Data - KeynesYouDigIt/Knowledge GitHub Wiki
For an excellent deep dive of encoding at the time of writing this, see https://github.com/KeynesYouDigIt/Knowledge/wiki/1.4-Encoding-and-Evolution#formats-for-encoding-data .
JSON is flexible and fast, XML is sturdy and slow, CSVs can be understood/written by non-technical audiences (and other than that are a tiny bit more structured than json but very similar)