Without &rand= trade is executed only once and on next command instead of opening another trade server returns confirmation of previously executed trade.
Zorro version 1.50, but https doesn't work.

My last working version:

Code:
// ------------------------- Trade4me/binary.com API - 2

function Trade4me( string Instrument, string Direction, string Exp, string Size)
{
  char ip_str[100]; // just a long empty string
  string httpline[200];
  sprintf(httpline,"http://trade4.me/order.php?username=Fiber100&password=Awainter1t&asset=%s&direction=%s&expiry=%s&amount=%s&rand=",Instrument,Direction,Exp,Size);
  int id = http_post(httpline,"123");
  if(!id) return;
  while(!http_status(id)) {
    if(!wait(100)) return; // wait for the server to reply
    printf(".");
  }  if(http_status(id) > 0) { //transfer successful?
    http_result(id,ip_str,100);   //get the replied IP
    printf("n%s",ip_str);
  } else
    printf("nError during transfer!");
  http_free(id); //always clean up the id!
}

function main()
{
	Trade4me ("EUR/USD","UP","5","10");
}