How to get response in web application after successfull login as callback?

You can use the widget’s events methods, for a successfull response for example:

ok = (credential) => {
syncWidget.$on('success', ok);

You will see something like this on the logs:

  "id_credential": "5ea3538f8a2b5d17953eb95d",
  "id_job_uuid": "5ea366a5424c4c0df366771d",
  "id_job": "5ea366a5424c4c0df366771e",
  "is_new": 0,
  "username": "E***********6",
  "ws": "wss://",
  "status": "",
  "twofa": ""

You can read more about Widget’s events in this link to the oficial documentation: