In performance tests on production hardware the node.js application responded to requests on average 35 percent faster than the Java alternative, resulting in the same page being served 200ms ...

Then Node.js was spawned, turning developers’ heads with its speed. Not only was JavaScript faster on the server than anyone had expected, but it was often faster than Java and other options.

Node.js offers speed and a nonblocking I/O API. Node.js was created because concurrency is difficult in many server-side programming languages, and often leads to poor performance.