The Clojure library sente allows you to do smooth web-socket work in Clojure. In our case, we wanted the typical “Your Session Expires in N seconds” alert for users of the app. Sente was working smoothly on our local machines, but we were getting obscure errors in the console about 500 responses in our browser console. The Problem As mentioned, our console was showing server errors on the path that was supposed to be doing the Sente channels.