> For the complete documentation index, see [llms.txt](https://k4k3ru.gitbook.io/k4k3ru-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://k4k3ru.gitbook.io/k4k3ru-docs/api/market-hub/bbo-subscribe.md).

# Subscribe to Consolidated BBO

`MarketHub.BBO.Subscribe` creates an authenticated WebSocket subscription for venue-independent, bid-anchored non-crossed best bid and offer updates. Use `MarketHub.BBO.Unsubscribe` with the same normalized parameters to remove it.

## Subscribe

```json
{
  "id": "1",
  "method": "MarketHub.BBO.Subscribe",
  "params": {
    "marketType": "spot",
    "symbol": "BTC/USDC"
  },
  "auth": {
    "apiKey": "YOUR_API_KEY",
    "timestamp": 1788533857,
    "nonce": "UNIQUE_NONCE",
    "signature": "REQUEST_SIGNATURE"
  }
}
```

The acknowledgement returns the normalized subscription parameters. Subsequent `bbo` events contain the same compact BBO result fields documented by [Get a Consolidated BBO Snapshot](/k4k3ru-docs/api/market-hub/get-bbo-snapshot.md).

## Unsubscribe

```json
{
  "id": "2",
  "method": "MarketHub.BBO.Unsubscribe",
  "params": {
    "marketType": "spot",
    "symbol": "BTC/USDC"
  },
  "auth": {
    "apiKey": "YOUR_API_KEY",
    "timestamp": 1788533860,
    "nonce": "ANOTHER_UNIQUE_NONCE",
    "signature": "REQUEST_SIGNATURE"
  }
}
```

Subscribe and Unsubscribe require valid signed WebSocket requests. Individual contributing Venue names are not returned.

OrderBook depth changes also trigger BBO evaluation because the retained best ask may be deeper than a source's original best ask. The same non-crossed consolidation and availability rules as Get apply.


---

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