how to get data through API?what is APIkey?

inthat how to use httprequest and  httpresponse and display data json format..

how to get below data in json format using API..

Request :

 

BODY:

            {

                        "classtype_id":670,

                        "seats":C8,c9,

"apikey": your api key,

"password": your password

"multiplex_id": 51(your multiplex_id)

            }         

           

 

Response:

           

For Successful booking

                        {

"result":"OK",

"booking_id":"121"

}

            For seats that already booked

                        {         

"result":"fail",

"booking_id":null

}

           

Fail

{

"result":"fail",

"message":"Insufficient Arguments"

}