pebble.js

  var body = {message: 'Hello "\u2764\uFE0F" one two three four'};
  bodyjson = JSON.stringify(body);  
  request.open('POST', "http://192.168.1.30:5000/", true);
  request.setRequestHeader('Content-Type', 'application/json');
  request.send(bodyjson);
  
  //iOS Sends:
  //{"message":"Hello \"❤️\" one two three fo
  
  //Android Sends:
  //{"message":"Hello \"❤️\" one two three four"}