Mirror API Playground

Question

When I enter my Client Id of an app that is authorized for Mirror API on the Mirror API Playground, and click Authorize, it opens an oAuth screen with an error:

Error: origin_mismatch
Request Details
scope=https://www.googleapis.com/auth/glass.timeline
response_type=token
access_type=online
redirect_uri=postmessage
proxy=oauth2relay706906217
origin=https://mirror-api-playground.appspot.com
state=697419930|0.9593537
display=page
client_id=111111111111.apps.googleusercontent.com
authuser=0

Answer 1

I was missing one step in the process which is adding https://mirror-api-playground.appspot.com to the JavaScript origins for the web application client id.