Improve OKX margin mode setup

- Fix use of `tgtCcy` for spot margin trading
- Add robust error handling for empty/invalid currency codes in balances

Author: cjdsellers

crates/adapters/okx/src/common/parse.rs

@@ -1378,19 +1378,58 @@ pub fn parse_account_state(
     let mut balances = Vec::new();
     for b in &okx_account.details {
         // Skip balances with empty or whitespace-only currency codes
-        let ccy_str = b.ccy.trim();
+        let ccy_str = b.ccy.as_str().trim();
         if ccy_str.is_empty() {
-            tracing::warn!(
+            tracing::debug!(
                 "Skipping balance detail with empty currency code (cash_bal={}, avail_bal={})",
                 b.cash_bal,
                 b.avail_bal
             );
             continue;
         }
 
-        let currency = Currency::from(ccy_str);
-        let total = Money::new(b.cash_bal.parse::<f64>()?, currency);
-        let free = Money::new(b.avail_bal.parse::<f64>()?, currency);
+        // Attempt to parse the currency, skip if invalid
+        let currency = match Currency::from_str(ccy_str) {
+            Ok(c) => c,
+            Err(e) => {
+                tracing::warn!(
+                    "Skipping balance detail with invalid currency code '{}' (cash_bal={}, avail_bal={}): {}",
+                    ccy_str,
+                    b.cash_bal,
+                    b.avail_bal,
+                    e
+                );
+                continue;
+            }
+        };
+
+        // Parse balance values, skip if invalid
+        let total = match b.cash_bal.parse::<f64>() {
+            Ok(v) => Money::new(v, currency),
+            Err(e) => {
+                tracing::warn!(
+                    "Skipping balance detail for {} with invalid cash_bal '{}': {}",
+                    ccy_str,
+                    b.cash_bal,
+                    e
+                );
+                continue;
+            }
+        };
+
+        let free = match b.avail_bal.parse::<f64>() {
+            Ok(v) => Money::new(v, currency),
+            Err(e) => {
+                tracing::warn!(
+                    "Skipping balance detail for {} with invalid avail_bal '{}': {}",
+                    ccy_str,
+                    b.avail_bal,
+                    e
+                );
+                continue;
+            }
+        };
+
         let locked = total - free;
         let balance = AccountBalance::new(total, locked, free);
         balances.push(balance);

crates/adapters/okx/src/websocket/client.rs

@@ -2377,7 +2377,11 @@ impl OKXWebSocketClient {
         // OKX API default behavior for SPOT market orders:
         // - BUY orders default to tgtCcy=quote_ccy (sz represents quote currency amount)
         // - SELL orders default to tgtCcy=base_ccy (sz represents base currency amount)
-        if instrument_type == OKXInstrumentType::Spot && order_type == OrderType::Market {
+        // Note: tgtCcy is only supported for cash (non-margin) trading
+        if instrument_type == OKXInstrumentType::Spot
+            && order_type == OrderType::Market
+            && td_mode == OKXTradeMode::Cash
+        {
             match quote_quantity {
                 Some(true) => {
                     // Explicitly request quote currency sizing

examples/live/okx/okx_exec_tester.py

@@ -27,6 +27,7 @@
 from nautilus_trader.config import TradingNodeConfig
 from nautilus_trader.core.nautilus_pyo3 import OKXContractType
 from nautilus_trader.core.nautilus_pyo3 import OKXInstrumentType
+from nautilus_trader.core.nautilus_pyo3 import OKXMarginMode
 from nautilus_trader.live.config import LiveRiskEngineConfig
 from nautilus_trader.live.node import TradingNode
 from nautilus_trader.model.enums import TimeInForce
@@ -162,7 +163,7 @@
             ),
             instrument_types=instrument_types,
             contract_types=contract_types,
-            # margin_mode=OKXMarginMode.ISOLATED,
+            margin_mode=OKXMarginMode.CROSS,
             use_spot_margin=False,
             # use_mm_mass_cancel=True,
             is_demo=False,  # If client uses the demo API

nautilus_trader/adapters/okx/config.py

@@ -109,14 +109,15 @@ class OKXExecClientConfig(LiveExecClientConfig, frozen=True):
     is_demo : bool, default False
         If the client is connecting to the OKX demo API.
     margin_mode : OKXMarginMode, optional
-        The intended OKX account margin mode for derivatives trading (SWAP/FUTURES/OPTIONS).
-        - `ISOLATED`: Margin isolated to specific positions (default for derivatives)
-        - `CROSS`: Margin shared across all positions
-        Not applicable for SPOT trading (see `use_spot_margin` instead).
+        The intended OKX account margin mode.
+        - `ISOLATED`: Margin isolated to specific positions (default)
+        - `CROSS`: Margin shared across all positions (enables cross margin for SPOT and derivatives)
+        When combined with `use_spot_margin=True`, this determines the margin mode for SPOT trading.
     use_spot_margin : bool, default False
-        If True, enables margin/leverage for SPOT trading (uses 'spot_isolated' trade mode).
+        If True, enables margin/leverage for SPOT trading.
+        The margin mode is determined by `margin_mode` (CROSS or ISOLATED).
         If False, uses simple SPOT trading without leverage (uses 'cash' trade mode).
-        Only applicable when trading SPOT instruments.
+        Note: SPOT_ISOLATED mode is only available for OKX copy traders and lead traders.
     max_retries : PositiveInt, default 3
         The maximum retry attempts for requests.
     retry_delay_initial_ms : PositiveInt, default 1_000

nautilus_trader/adapters/okx/execution.py

@@ -180,7 +180,12 @@ def __init__(
         if account_type == AccountType.CASH:
             # SPOT trading
             if config.use_spot_margin:
-                self._trade_mode = OKXTradeMode.SPOT_ISOLATED
+                # Use CROSS margin mode for spot margin trading
+                # Note: SPOT_ISOLATED is only available for copy traders
+                if config.margin_mode == OKXMarginMode.CROSS:
+                    self._trade_mode = OKXTradeMode.CROSS
+                else:
+                    self._trade_mode = OKXTradeMode.ISOLATED
             else:
                 self._trade_mode = OKXTradeMode.CASH
         else:
@@ -745,8 +750,19 @@ def _get_trade_mode_for_order(
             return self._trade_mode
 
         if isinstance(instrument, CurrencyPair):
-            return OKXTradeMode.SPOT_ISOLATED if self._config.use_spot_margin else OKXTradeMode.CASH
+            # SPOT trading
+            if self._config.use_spot_margin:
+                # Use CROSS or ISOLATED margin mode for spot margin trading
+                # Note: SPOT_ISOLATED is only available for copy traders
+                return (
+                    OKXTradeMode.CROSS
+                    if self._config.margin_mode == OKXMarginMode.CROSS
+                    else OKXTradeMode.ISOLATED
+                )
+            else:
+                return OKXTradeMode.CASH
         else:
+            # Derivatives trading
             return (
                 OKXTradeMode.CROSS
                 if self._config.margin_mode == OKXMarginMode.CROSS