Evan Miller's guide (already linked above) is great. But be prepared to dig into the Nginx code. Most things aren't documented, however, at least in my opinio

Evan Miller's guide (already linked above) is great. But be prepared to dig into the Nginx code. Most things aren't documented, however, at least in my opinion, it has some of the cleanest large scale C code around. So, don't be scared to dig in.