> ## 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.

# Rust Perps Stream

> Subscribe to managed Rust perps tickers, BBO, full books, trades, statistics, and klines.

```rust theme={null}
use polynode::{
    bbo_channel, book_channel, klines_channel, ticker_channel, trades_channel,
    PerpsMessage, PolyNodeClient,
};

#[tokio::main]
async fn main() -> polynode::Result<()> {
    let client = PolyNodeClient::new(
        std::env::var("POLYNODE_API_KEY").expect("Set POLYNODE_API_KEY")
    )?;
    let mut perps = client.perps_stream().await?;

    let ack = perps.subscribe(vec![
        ticker_channel(),
        bbo_channel("BTC-USD")?,
        book_channel("BTC-USD")?,
        trades_channel("BTC-USD")?,
        klines_channel("BTC-USD", "1m")?,
    ]).await?;

    if !ack.rejected.is_empty() {
        eprintln!("rejected channels: {:?}", ack.rejected);
    }

    while let Some(message) = perps.next().await {
        match message? {
            PerpsMessage::Event(event) => println!("{event:?}"),
            PerpsMessage::Reconnected(notice) => {
                eprintln!("gap possible: {}", notice.gap_possible);
            }
            PerpsMessage::LagWarning(warning) => eprintln!("{warning:?}"),
            PerpsMessage::Unknown { raw, decode_error } => {
                println!("unknown: {raw} {decode_error:?}");
            }
            _ => {}
        }
    }

    perps.close().await?;
    Ok(())
}
```

One subscribe request can be partially accepted. Inspect `ack.channels` and `ack.rejected`.

Each `PerpsEvent::Book` is a complete replacement, not an incremental patch. `perps.book("BTC-USD").await` returns the latest managed copy, or `None` until the first book event arrives. A successful acknowledgement confirms the channel, not book readiness; use the [V3 perps orderbook](/perps/market-data/book) when startup needs immediate state.

The client reconnects and resubscribes after non-terminal disconnects, but replay is not guaranteed. `PerpsReconnectNotice.gap_possible` is true; use V3 REST to backfill if completeness matters. Authentication (`4401`) and connection-limit (`4429`) closes are terminal until the failing condition changes.

The bounded receive channel applies backpressure. Poll `next()` continuously and move slow work to a bounded worker pipeline.

See the [shared perps guide](/sdks/perps) for channel definitions and lifecycle details.