gistfile1.json

{
    "list_of_things": [
        "/v0/things/1"
    ],
    "_links": {
        "self": "/v0/things",
        "next": "/v0/things?page=2"
    },
    "_embedded": {
        "/v0/foos/3": {
            "id": 3,
            "_links": {
                "self": "/v0/foos/3"
            }
        },
        "/v0/things/1": {
            "id": 1,
            "some_relation": "/v0/foos/3",
            "whatever": {
                "other_relation": "/v0/bars/6",
                "blah_blah": 42
            },
            "_links": {
                "self": "/v0/things/1"
            }
        }
    }
}

Missing , after ].

Cannot use key–value pairs in arrays.

you "_embedded" object makes no sense, in particular, you seem to have variable keys