While Express is a very popular and widely used package that can be used to build any kind of server, if you specifically want just a REST server and no other feature, you may consider using other packages, such as Restify. The advantages of such a change have to do with the orientation of the package, which provides similar features to Express, but requires a bit less code in order to accomplish a RESTful deployment. Some well-known users of Restify are npm and Netflix, but the list is much longer.
You can read more about Restify at http://restify.com/.