title: Call Firebase Callable Cloud function Function from Admin SDK
body: <p>I have a Firebase cloud function that I would like to make a Callable function so that I can call it from my web clients with authentication built in. But I would also like to call it from my own back end code using the Admin SDK (specifically from Java) if that matters.</p>
  
  <p>I see that the <a href="https://firebase.google.com/docs/functions/callable-reference" rel="nofollow noreferrer">protocol is documented</a>, but I am a little unclear how to authenticate it from the Admin SDK. I know you can <a href="https://firebase.google.com/docs/reference/admin/java/reference/com/google/firebase/auth/FirebaseAuth.html#createCustomToken(java.lang.String)" rel="nofollow noreferrer">create a token</a>, but this doesn't seem to be the correct <code>Bearer</code> token that the Callable function expects. How can I generate one of those? Or is there a better way to call a Callable function securely from the Admin SDK?</p>