Using Meteor as a classic backend

I'm wondering if Meteor can be used as a classic backend for a Rest API and websockets.

I found Restivus[1] which is spectacular, I can turn Meteor into a full Rest API with security and everything. But how to use sockets now ? It is the only part that I can't found.

I found this approach interesting so I can build a backend for already existing front ends (angular/ember) and also for DDP clients.

This way I don't have to build two different backends based on different frameworks (express for classic Rest API and Meteor for DDP).

Thanks.