Lots of insight—and several great projects—on their blog: https://code.facebook.com https://code.facebook.com Things work a little different for Facebook than

Lots of insight—and several great projects—on their blog: https://code.facebook.com https://code.facebook.com Things work a little different for Facebook than they do for sites with more reasonable traffic. I've seen a few talks on YouTube where they speak about the challenges of scalability as they gradually hot swap legacy X or Y for their own in-house component Z. See React/JSX and Flux, and the Haxl library. They go into detail about some of the problems and solutions that they've made public with respect to those projects, and they speak a lot about testing too in many of the posts. Worth checking out.