Available parameters and response documentation is available here

GET /lookup/chr12:25398284:C:T
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Content-Type: application/json ;utf-8
ETag: "e20697061e5fc5a54fd2f8b2d126e9bad16e284af771447cb99ee0567aa6b45f"
Vary: Accept

{
  "chromosome": "chr12",
  "alt": "T",
  "ref": "C",
  "pos": 25398284,
  "variant_id": "10190120253982840004",
  "variant_type": "SNV",
  "cytobands": "12p12.1",
  "publications": {
    "publications": [],
    "genes": []
  },
  "publication_counts": [
    {
      "type": "variant",
      "id": "10190120253982840004",
      "count": 1840
    }
  ]
}