data.json

{
  "properties": {
    "SSN1" : {
        "first": "Joe",
        "last": "Doe"
    },
    "SSN2": {
        "first": "Mary",
        "last": "Jane"
    }
  }
}

JsonPathArgo.purs

newtype A = A {
  properties :: StrMap B
}

newtype B = B {
  first :: String,
  last :: String,
  ssn :: String
}