Use YAML because YAML supports comments YAML supports JSON (you can actually write JSON syntax that YAML can parse) https://github.com/datatxt/awseome-yaml#json https://github.com/dreftymac/awesome-yaml Use JSON because You do not have access to a YAML library in your chosen programming language You are intimidated by the fact that YAML isn't JSON and you are under political/social pressure to follow the herd