Replicate: Create two models with `parent` and `children` relationship. Try to `POST` a new `parent with no children. Expect: `201` Get: `400` The `children` field is required. This can be solved by extending the serializer as described in this thread: http://discuss.emberjs.com/t/ember-data-1-13-7-using-jsonapi-how-to-post-hasmany-relationships-in-one-payload/8727/7 However, I would expect the adapter to handle this somehow. But maybe it's entirely Ember's fault!