Firebase: HTTP POSTing Notification from Android App returns success but nothing happens

Question

I'm trying to post a notification directly from my App instead of using Firebase console. The code I wrote is this:

    URL url= null;
    HttpURLConnection client = null;
    try{
        url = new URL("https://fcm.googleapis.com/fcm/send");
        client = (HttpURLConnection) url.openConnection();
        client.setDoOutput(true);

        client.setRequestMethod("POST");
        client.setRequestProperty("Content-Type", "application/json");
        client.setRequestProperty("Accept", "application/json");
        client.setRequestProperty("Authorization", "key=<here my server key from firebase site");
        client.setRequestProperty("project_id", "<here my sender ID from firebase site");
        client.connect();


        JSONObject payload = new JSONObject();
        payload.put("body",news.text);
        payload.put("title",news.title);


        JSONObject notif = new JSONObject();
        notif.put("to", "/topics/MyFirstTopic");
        notif.put("notification", payload);

        OutputStream outputPost = client.getOutputStream();
        outputPost.write(notif.toString().getBytes("UTF-8"));
        outputPost.flush();
        outputPost.close();

        // Read the response into a string
        InputStream is = client.getInputStream();
        String responseString = new Scanner(is, "UTF-8").useDelimiter("\\A").next();
        is.close();

    }
    catch(Exception e) {
        if (e.getMessage() != null) {
            Log.e("SEND NOTIF TO FB", e.getMessage());
        }
        else {
            Log.e("SEND NOTIF TO FB", e.toString());
        }
    }
    finally {
        if(client!=null) client.disconnect();
    }

The code runs without errors and the response (in responseString) is apparently correct:

{
  "message_id": "123456789..."
}

but in Firebase Console (in Notifications page) I can't see the posted notification neither devices receive it.

What am I missing??

Note: for beeing concise I didn't post here permission settings and code for threating notification (onMessageReceive...) but I can guarantee that it works with notifications sent from Firebase Console.

Answer 1

The Firebase Notifications console only shows messages that were sent from the console itself. It does not show messages that you sent through the Firebase Cloud Messaging API.