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

# Best Bid/Offer

> Top-of-book price and size for one or all instruments.

```bash theme={null}
# All instruments
curl "https://api.polynode.dev/v3/perps/bbo?key=$POLYNODE_API_KEY"

# One instrument
curl "https://api.polynode.dev/v3/perps/bbo/eth?key=$POLYNODE_API_KEY"
```

```json theme={null}
{
  "instrument_id": 7,
  "symbol": "ETH-USD",
  "bid_price": "1729.7",
  "bid_quantity": "0.5653",
  "ask_price": "1729.8",
  "ask_quantity": "3.7577",
  "timestamp": 1783571033336
}
```

Lighter than fetching the full [book](/perps/market-data/book) when you only need the touch. Streams as [`perps_bbo:<instrument>`](/perps/websocket/channels).