JSON stands for JavaScript Object Notation. It is a compact data format in an easily readable text form. It is used, for example, to persist structured data or to exchange information between applications. Especially for web applications and mobile apps it is very often used in connection with JavaScript, for example when using REST services.
JSON is independent of the programming language in which it is used. Thus, programs developed in different programming languages can communicate with each other using JSON. It is only important that the various JSON parsers adhere to the conventions of the JSON format.
Data can be nested arbitrarily deep in a JSON object. In this way, very complex JSON structures can be created. In order to ensure that such JSON objects remain readable for humans, proper formatting by indentations and line breaks is used. It makes sense to use a tool like the JSON formatter for this purpose. A JSON object formatted in this way is also called pretty printed JSON.