if you are making JSON data to use in your language and application you will probably not have any problem. But as in any thing there can interoperability issue

if you are making JSON data to use in your language and application you will probably not have any problem. But as in any thing there can interoperability issues between implementations and programming languages - especially if your JSON is being generated and consumed by your JavaScript site some potential issues https://bishopfox.com/blog/json-interoperability-vulnerabilities https://bishopfox.com/blog/json-interoperability-vulnerabili... on edit: not parent commenter of course, just what I think they might have meant.