> ## Documentation Index
> Fetch the complete documentation index at: https://docs.whitebit.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Book Ticker

> Subscribe to real-time best bid and ask price updates for trading pairs via WhiteBIT WebSocket.

Real-time best bid and best ask price updates for a market. The server sends an update instantly whenever the best bid or best ask changes. Each update contains the current best bid price, best bid amount, best ask price, and best ask amount for the subscribed market. Use this stream to maintain an accurate top-of-book view without polling the REST API.

<Note>Connect to `wss://api.whitebit.com/ws` — see [WebSocket Overview](/websocket/overview) for protocol details and keepalive requirements.</Note>

## Rate limits

## Subscribe to book ticker

## Update frequency

Updates are pushed **instantly** on every best bid or offer change.

## Error codes

<Note>
  Public `bookTicker_update` events exclude Retail Price Improvement (RPI) orders. The stream includes only regular order book liquidity. RPI orders are visible in private active order endpoints and in the exchange UI order book.
</Note>

## Book ticker update object