For security reasons it would be super handy if it would be possible to handle api calls to third party systems which contain a constant token via the Magnolia backend. Specifically I would like to use a light-development defined RestClient. 

The idea would be to send a postMessage to the backend like:

parent.window.postMessage(
    {
      action: 'callRestClient',
      correlationId,
      value: <restClientName>,
      body: <restBody>
    },
    '*'
  ); 

And then use the EventListener to receive the results:

window.addEventListener('message', function (event) {
  if (event.data.action === 'restCall') {
    console.log(event.data.response);
  },
  false
);