this.route('rawdata', {
  path: '/raw/:collection',
  layoutTemplate: 'nolayout',
  template: 'raw'
})

<template name="direct_layout">
    {{> yield}}
</template>

this.route('rawdata', {
    path: '/raw/:collection',
    layoutTemplate: 'direct_layout',
    template: 'raw'
});

this.route('serverRoute', {
  where: 'server',
  path: '/your-route',
  action: function() {
    var data = {this_is:'a json object'}


    this.response.writeHead(200, {'Content-Type': 'application/json'});
    this.response.end(JSON.stringify(data));
  }
});