What is a json file and how do I open a json file?

A .JSON file, or JavaScript Object Notation, is an open standard format that uses readable text to transmit data objects consisting of attribute-value pairs. The JSON file format is used to transmit structured data over various network connections. Mozilla JSON files created in a Firefox browser also contain backup copies of a user's bookmarks. Though .JSON was originally derived from the JavaScript scripting language, JSON is a language-independent data format. Code for parsing and generating JSON data is readily available in many programming languages. JSON generally ignores any whitespace around or between syntactic elements (values and punctuation, but not within a string value). However JSON only recognizes four specific white space characters: the space, horizontal tab, line feed, and carriage return. JSON doesn't provide or permit any sort of comment syntax. JSON is a way to store information in an organized, easy-to-access manner. In a nutshell, it gives us a human-readable collection of data that we can access in a really logical manner.
Because of AJAX-powered sites, it became more and more important for sites to be able to load data quickly, or in the background without delaying page rendering. Because of the popularity and ease of social media, many sites rely on the content supplied by websites such as , Flickr, Twitter, and others. Any sites that provide RSS feeds, which are simple to import and use on the server-side, but when they are loaded with AJAX, an issue arises. When loaded it is only possible to load an RSS feed if it is being requested from the same domain it’s hosted on. JSON allows us to overcome the cross-domain issue thanks to a method called JSONP that uses a callback function to send the JSON data back to our domain. It’s this functionality which makes JSON so very useful, as it corrects many issues that were previously difficult to work around.