Request the following URL:

https://echo.tinkink.net/echo?data={"hello":"world"}&mime=json

You get:

{"hello":"world"}

Examples:

var mockData = {
  status:1,
  text:'hello world'
};

var url = 'https://echo.tinkink.net/echo?data=' +
  JSON.stringify(mockData) +
  '&mime=json';

$.post(url).done(function(data){
  // data equals mockData
  // {status:1, text:"hello world"}
  console.log(data);
});
	

More Docs: