Errors#

What methods return#

Every ExchangeTrader method returns anyhow::Result<T>. Network failures, signature problems, exchange error codes and "not implemented" cases all arrive as an anyhow::Error with a message. Print it with {e:#} to see the whole context chain.

match trader.get_balance().await {
    Ok(b) => println!("{}", b.available_balance),
    Err(e) => eprintln!("balance failed: {e:#}"),
}

Rejected orders#

Order methods return Result<OrderResult>. A request the exchange refuses may come back as Ok with success == false and a message in error, not as Err. Check both:

match trader.place_market_order("BTCUSDT", OrderSide::Buy, 0.001).await {
    Ok(r) if r.success => println!("filled {}", r.order_id()),
    Ok(r)              => eprintln!("rejected: {:?}", r.error),
    Err(e)             => eprintln!("request failed: {e:#}"),
}

Err means the call itself failed, for example a network error or a malformed response. Ok with success == false means the exchange answered and said no.

"Not implemented"#

Optional trait methods that an adapter does not override return an error shaped like get_ticker not implemented for <exchange>. Check capabilities before calling optional methods on adapters you have not used.

ExchangeError#

tradersdk_core::ExchangeError (re-exported in the prelude) is a typed error enum:

Variant	Meaning
`Network(reqwest::Error)`	Network error during an API call.
`Authentication(String)`	Authentication failed.
`InvalidResponse(String)`	The response could not be understood.
`RateLimited { retry_after_ms }`	Rate limit exceeded.
`OrderRejected(String)`	Order rejected by the exchange.
`InsufficientFunds(String)`	Not enough balance.
`SymbolNotFound(String)`	Unknown symbol.
`InvalidOrder(String)`	Invalid order parameters.
`PositionNotFound(String)`	No such position.
`WebSocket(String)`	WebSocket error.
`ExchangeSpecific { exchange, code, message }`	An exchange-specific error code.
`Other(String)`	Anything else.

It has constructors (ExchangeError::auth("..."), rate_limited(ms), ...) and helpers:

is_retryable() is true for Network, RateLimited and WebSocket.
is_rate_limited() and retry_after() (milliseconds).

Adapters do not return ExchangeError yet. The bundled adapters return anyhow errors built from messages, so err.downcast_ref::<ExchangeError>() will usually find nothing. Use ExchangeError in your own code and in new adapters, and match on error messages for the built-in ones until the adapters adopt the typed variants.

Retrying#

The tradersdk-utils crate has retry, rate-limiting and circuit-breaking helpers. See Utilities. Do not blindly retry order placement: a request that timed out may still have reached the exchange. Check the order status before sending it again.