Building a Restful API with Express is an easy process in the fundamental phase. Once you start getting requirements in, it becomes a handcraft to keep the code clean and tidy.
I found an article that brings us some tips and modules to improve the security and performance of a Restful API.
Morgan: HTTP request logger middleware for node.js
Cluster: For parallel processing and multi-core server manager.
Compression: For GZIP content compression.
Helmet: For securing Express/Connect apps with various HTTP headers.
The article also shows how to setup content through SSL and HTTPS.