Available parameters and response documentation is available here

GET /lookup/chr19:20082943:1:G
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json ;utf-8
ETag: "c841f45508a1c97f1bad2514d98bbc65d8a3b3750906337c23042a6dea5a0864"
Vary: Accept

{
  "chromosome": "chr19",
  "alt": "G",
  "ref": "T",
  "pos": 20082943,
  "variant_id": "10190190200829430003",
  "variant_type": "SNV",
  "cytobands": "19p12",
  "publications": {
    "publications": [],
    "genes": []
  },
  "publication_counts": [
    {
      "type": "variant",
      "id": "10190190200829430003",
      "count": 0
    }
  ]
}