Simple authentication in node.js with a token only?

I'm developing an API that requires a very minimal amount of security that will be consumed by mobile clients. We have a separate server that handles user accounts and authorization, so I would like (if possible) to design an authentication system where the user (mobile app) only has to use a token to access the API. What are my options for this kind of authentication? What's the best way to set something like this up with node/express?

Submitted April 13, 2016 at 09:39PM by estebanrules