The Questrade package writes the Questrade key to disk on the file system for data storage:

Questrade.prototype._saveKey = function (cb) {
  cb = cb || function(){};
  var self = this;
  fs.writeFile(self._getKeyFile(), self.refreshToken, 'utf8', function (err) {
    if (err) return cb({ message: 'failed_to_write', details: err });
    cb(null, self.refreshToken);
  });
}

If running on a service like Heroku with an ephemeral file system, the data will not persist and the API key will not be valid. TODO: Write the temp key to a database and retrieve it when requested by the Questrade package.

I think that Questrade "personal apps" API tokens expire entirely if they are not used for over 7 days. In order to test, need to not use the app for > 7 days and see if it can re-validate itself. See: https://login.questrade.com/APIAccess/userapps.aspx

Unfortunately this app is dead in the water until I can get a new Questrade API token. I've tried to refresh my token "manually" but to no avail!

I'll file an issue with QT and report back. Until then this app will not work.