Load Balancing with Nginx

How can the task API answer more requests than one machine can handle, and keep answering while one machine restarts? The answer is load balancing: several copies of the app run at the same time, and one server in front of them spreads the requests over the copies. That server also changes what Express sees in every request, so the app needs one setting to match.

Spreading Requests over Several Servers

A load balancer is a server that receives every request from clients and forwards each one to one of several copies of your app, called backends or upstream servers