JSON
Number: 123
Boolean: true/false
Null: null
String: "abc"
Object: {"attribute":123, "attribute2":true, "attreibute3":{"A":65. "B":66}}
Array: [123, "abc",98]

API Version
    option1: Add API version in path
    option2: Add API version in http header

CRUD: HTTP verbs
Create(POST), Read(GET), Update(PUT), Delete(DELETE), payload: json

http status codes
200: ok 201: created 204: No Content
304: Not Modified
400: Bad Request
401: Not Authorized
404: Not Found
500: Internal Server Error
>>> Create a User
POST /users
request:
{
    "username": "Chang"
    "User Status": "Gold"
}
or
request:
{
    "user ID": 17,
    "Username": "Chang",
    "usrt Status": "Gold"
}
>>> Get All Users
GET /users
request:
response:
[
    { "user id":1, "username": "chang", "user status":"gold"},
    { "user id":2, "username": "lee", "user status":"silver"},
]
>>> Get a user with a given ID
GET /users/{userid}
response: { "user id":1, "username": "chang", "user status":"gold"}
>>> Update a user
PUT /users/{userid}
request: {"user id":1, "username": "chang", "user status":"silver"}
response: {"user id":1, "username": "chang", "user status":"silver"}
>>> Delete a user
DELETE /users/{userid}
request:
response: 204
>>> Friends
POST /users/{userid}/friends
GET /users/{userid}/friends
GET /user/{userid}/friends/{friendid}
   /friends/{friendid}
PUT /users/{userid}friend/{friendid}
    /friend/{friendid}
DELETE /user/{userid}/friend/{friendid}
       /friend/{friendid}