title: Exchange reference token for JWT - downstream microservices authorization
body: <p>I am currently creating a new application based on a Microservices architecture, with authentication provided by Identity Server 4. </p>
  
  <p>Following lots of research and also setting up proof of concepts, I have Identity Server setup to secure the API's and a native application successfully accessing these services using tokens.</p>
  
  <p>Initially the client was issued an access token which was used to access the API's, I have however now switched this out to use reference tokens.  Now, onto the issue!</p>
  
  <p>The approach I would like to take here is to adopt a Microservices gateway, which receives a reference token and then turns this into a JWT for inclusion in any requests to the downstream microservices.  Within the Gateway, how can I "exchange" the inbound reference token for a JWT? Is there something within Identity Server that can assist here? Or do I need to use the introspection endpoint, sending in the reference token and retrieving the claims to construct a JWT within the gateway service for passing in the Authorization header to all downstream services?</p>
  
  <p>If there is any further information that I can provide to help with understanding the goal of the architecture, please just let me know.</p>