> For the complete documentation index, see [llms.txt](https://ajaib.gitbook.io/ajaib-exchange-open-api/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ajaib.gitbook.io/ajaib-exchange-open-api/websocket-references/web-socket-streams/partial-book-depth.md).

# Partial Book Depth

**Functionality:** To subscribe partial book depth event stream.

**Authentication:** Required

**Stream Name:** \<symbol>@depth\<level>

> Valid \<level> are 5, 10, 20, or 50.

**Update Time:** 500ms

> Note: this WebSocket stream will return 12 levels of order book depth.

Response

<table><thead><tr><th width="145">Name</th><th width="210">Type</th><th>Description</th></tr></thead><tbody><tr><td>lastUpdateId</td><td>integer</td><td>Order book last update ID</td></tr><tr><td>e</td><td>string</td><td>Websocket event type</td></tr><tr><td>s</td><td>string</td><td>The trading pair symbol. Refer to <a href="https://ajaib.gitbook.io/coin-exchange-open-api/getting-started/quickstart#:~:text=Asset%20Symbols%20/%20Trading%20Pairs">this</a>.</td></tr><tr><td>bids</td><td>List of DepthData</td><td>Represents buy orders in the order book</td></tr><tr><td>asks</td><td>List of DepthData</td><td>Represents sell orders in the order book</td></tr></tbody></table>

#### Response Body Object > DepthData&#x20;

<table><thead><tr><th width="148">Index</th><th width="213">Type</th><th>Description</th></tr></thead><tbody><tr><td>0</td><td>string</td><td>Price level</td></tr><tr><td>1</td><td>string</td><td>Quantity</td></tr></tbody></table>

Response Sample

{% tabs %}
{% tab title="Success" %}

```javascript
{
  "lastUpdateId": 26513,
  "e": "depth",
  "s": "BTC_USDT",
  "bids": [
    [
      "95000",
      "10"
    ]
  ],
  "asks": [
    [
      "96000",
      "100"
    ]
  ]
}
```

{% endtab %}
{% endtabs %}