Most tutorials online suggests using reverse proxy with TCP socket. I use UNIX socket. I consider it faster - it circumvents all TCP bloat:

fs.unlink "/tmp/app.sock", (err) ->
    app.listen "/tmp/app.sock"
    setTimeout () ->
        fs.chmod "/tmp/app.sock", 0x777, (callback) ->
    , 2000

Code above removes old socket (if any), starts express app and orders it to listen on /tmp/app.sock and finally changes permissions so nginx process running other user can connect to it (I believe it is not required on BSD systems).

Nginx part looks like this:

server {
    listen <your_ip_here>:80;
    location / {
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_pass http://unix:/tmp/app.sock;

That’s it.

P.S. node.js part is in CoffeeScript.