JSON is a format for transferring structured data. It is flexible, easy for computers to generate and parse, and relatively readable for humans. It has become very common as a means of persisting program data structures and transferring data between programs.
JSON has four basic types: Numbers, Strings, Booleans, and null, and two compound types: Arrays and Objects. Objects are unordered collections of key-value pairs, where the key is always a string and the value can be any simple or compound type. We have already seen a JSON object: the data returned by the API call api.github.com/users/odersky.
Arrays are ordered lists of simple or compound types. For instance, type api.github.com/users/odersky/repos in your browser to get an array of objects, each representing a GitHub repository:
[
{
"id": 17335228,
"name": "dotty",
"full_name": "odersky/dotty",
...
},
{
"id": 15053153,
"name": "frontend",
"full_name": "odersky/frontend",
...
