How to include route handlers in multiple files in Express?

If you want to put the routes in a separate file, for example routes.js, you can create the routes.js file in this way:

module.exports = function(app){

    app.get('/login', function(req, res){
        res.render('login', {
            title: 'Express Login'
        });
    });

    //other routes..
}

And then you can require it from app.js passing the app object in this way:

require('./routes')(app);

Have also a look at these examples

https://github.com/visionmedia/express/tree/master/examples/route-separation