curl --request GET \
  --url https://perp-api.phoenix.trade/v1/view/orderbook/{symbol} \
  --header 'Authorization: Bearer <token>'

{
  "asks": [
    [
      123,
      123
    ]
  ],
  "bids": [
    [
      123,
      123
    ]
  ],
  "slot": 1,
  "symbol": "<string>",
  "mid": 123,
  "splines": [
    {
      "askFilledAmount": "<string>",
      "askRegions": [
        {
          "density": 123,
          "end": 123,
          "filledSize": "<string>",
          "start": 123,
          "totalSize": "<string>"
        }
      ],
      "bidFilledAmount": "<string>",
      "bidRegions": [
        {
          "density": 123,
          "end": 123,
          "filledSize": "<string>",
          "start": 123,
          "totalSize": "<string>"
        }
      ],
      "midPrice": 123,
      "traderKey": "<string>"
    }
  ]
}