In this article we will understand how to go about using facebooks graph API in a Ruby on Rails web application. We will be using two gems to get the work done, omniauth-facebook and koala. Omniauth-Facebook and Koala Omniauth-facebook is facebook OAuth2 strategy for OmniAuth and as every OmniAuth strategy it is a Rack Middleware. Koala is a facebook library for ruby which supports facebook graph