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# Subscribe to BookTrader Price Ladder

#### Price Ladder Request

###### Topic:

**sbd**\
Subscribes the user to BookTrader price ladder data.\
Streaming BookTrader data requires users to maintain a L2, Depth of Book, market data subscription. See the [Market Data Subscriptions page](/general/market-data-subscriptions/) for more details.

###### Topic Target:

**acctId:** Required.\
Must pass a single AccountId.

**conids:** Required.\
Must pass a single contract identifier.

**exchange:** Optional.\
Provide a routing exchange identifier.\
If no exchange is specified, all available deep exchanges are assumed.

```
sbd+acctId+conid+exchange
```

#### Price Ladder Response

**topic:** String.\
Returns the request's topic string.

**data:** Array of Objects.\
Returns an array of objects to indicate ladder depth.

**row:** int.\
Returns the row identifier of the ladder data.

**focus:** int.\
Indicates if the value was marked as the last trade price for the contract.

**price:** String.\
Returns the Last, or last executed trade, price.\
In some instances, price and size will be returned in the structure '"price":"size @ price"'.

**ask:** String.\
Returns the corresponding ask size.

**bid:** String.\
Returns the corresponding bid size.

```
{
  "topic":"sbd+acctId+conid",
  "data":[
    {"row":0,"focus":0,"price":"price"},
    {"row":1,"focus":0,"price":"size @ price"},
    {"row":n,"focus":0,"price":"price", "bid":"bid"},
    {"row":n+1,"focus":0,"price":"price", "ask":"ask"},
    {"row":n+1,"focus":0,"price":"size @ price", "ask":"ask"}
  ]
}
```