Request Order Book Snapshots

The returned snapshots are the successful response; no intermediate acknowledgement is sent. UDX returns exactly one snapshot per requested sid in request order. Every returned snapshot echoes the command ID and consumes that subscription’s next sequence number. After a sequence gap, stop applying that sid until this snapshot replaces its complete local state; later messages then continue from the snapshot sequence.

RECEIVE/ws

Authorization

UDX-Access-KeyAPI key · headerrequired

API key signature over `timestamp + "GET" + "/ws"`. The channel binding lists the required upgrade headers.

UDX-Access-KeyAPI key · headerrequired

API key signature over `timestamp + "GET" + "/ws"`. The channel binding lists the required upgrade headers.

Message

idinteger<int64>required

Client-assigned command correlation ID, unique among commands in flight on this connection.

min 1 · max 9007199254740991

cmdstringrequired

Selects the snapshot command.

paramsobjectrequired

Selects order book subscriptions as a canonical array.

Show properties

sidsinteger<int64>[]required

Canonical non-empty list of distinct subscription IDs. It remains an array when one subscription is targeted.

min items 1 · max items 250

Channel bindings

ws

methodGET

headers

UDX-Access-Keystringrequired

Opaque API key ID.

min length 1 · max length 255

UDX-Access-Timestampstringrequired

Unix time in milliseconds.

max length 13 · matches ^[0-9]{13}$

UDX-Access-Signaturestringrequired

Base64 RSA-PSS/SHA-256 signature.

min length 1 · max length 1024

Sec-WebSocket-Protocolstringrequired

Negotiated dated WebSocket API version.

Example

wscat -c 'wss://api.uat.udx.underdogsports.com/ws'
> {"id":3,"cmd":"snapshot","params":{"sids":[7,8]}}

const socket = new WebSocket("wss://api.uat.udx.underdogsports.com/ws");

socket.addEventListener("open", () => {
  socket.send(JSON.stringify({
    "id": 3,
    "cmd": "snapshot",
    "params": {
      "sids": [
        7,
        8
      ]
    }
  }));
});

Message

{
  "id": 3,
  "cmd": "snapshot",
  "params": {
    "sids": [
      7,
      8
    ]
  }
}