Problems with POST through HTTP.request

Hi Guys - having issues getting an HTTP POST to work. Device is an espruino wifi, flashed to the latest version.

Here's the code:

var WIFI_NAME = "xxxx";
var WIFI_OPTIONS = { password : "yyy" };
var wifi = require("EspruinoWiFi");

wifi.connect(WIFI_NAME, WIFI_OPTIONS, function(err) {
  if (err) {
    console.log("Connection error: "+err);
    return;
  }
  console.log("Connected!");
  sendData();
  
});

function sendData() {
  var options = {
    host: 'http://192.168.1.66', // host name
    port: 8081,            // (optional) port, defaults to 80
    path: '/stats/login/',           // path sent to server
    method: 'POST',
    headers: { "Content-type" : "application/json" } 
  };
  
  
  var req = require("http").request(options, function(res) {
    
    console.log('res',res);
    
     res.on('error', function(data) {
      console.log("error> "+data);
    });
    
    res.on('data', function(data) {
      console.log("HTTP> "+data);
    });
    res.on('close', function(data) {
      console.log("Connection closed");
    });
  });
  
  req.end("{module:'espruino'}");  
  console.log("Request sent"); 

The connection works OK and I also get the 'request sent' message, but nothing after that on the espruino, and no connection received by the server.

I've verified that the endpoint (which is a server of mine) is working OK (accepts a POST from a REST client), and HTTP.GET works fine (copied one of the examples). I'm doubtless doing something basic wrong, but not sure how to debug further...