I need to integrate Firebase Authentication into Apigee. Specifically, I need to make use of the Admin SDK in order to create custom tokens and then verify them on subsequent calls. It appears that a Java Callout might be able to satisfy my needs - one for a login flow which creates the custom token and another that will sit in the policy chain for all calls requires authentication. I suppose I always have the option just to create a NodeJs app proxy that does all this. How should I approach this problem?