fix(trader): stop order-sync goroutine leak and rate-limit hammering

Every StartOrderSync spawned a ticker goroutine that ran forever — it
survived trader stop AND deletion, so each quick-created trader left a
permanent 30s Hyperliquid poll behind. Stacked leaks turned into an
~8s effective hammer that tripped Hyperliquid's 429 rate limit, which
then broke the symbol board, trader creation, and order sync itself.

- new trader/syncloop package: shared stoppable sync loop with
  exponential failure backoff (30s base, 5min cap)
- all 9 exchanges' StartOrderSync now take the trader's stop channel
  and stop when the trader stops (close broadcast from AutoTrader.Stop)
- provider/hyperliquid: GetPerpDexCoins now serves a 5min TTL cache and
  falls back to the stale board when the upstream returns 429, so the
  symbol panel keeps working through rate limiting

trader/aster/trader_sync.go

@@ -5,6 +5,7 @@ import (
 	"nofx/logger"
 	"nofx/market"
 	"nofx/store"
+	"nofx/trader/syncloop"
 	"sort"
 	"strings"
 	"time"
@@ -180,14 +181,8 @@ func deriveAsterOrderAction(side, positionSide string, realizedPnL float64) stri
 }
 
 // StartOrderSync starts background order sync task for Aster
-func (t *AsterTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration) {
-	ticker := time.NewTicker(interval)
-	go func() {
-		for range ticker.C {
-			if err := t.SyncOrdersFromAster(traderID, exchangeID, exchangeType, st); err != nil {
-				logger.Infof("⚠️  Aster order sync failed: %v", err)
-			}
-		}
-	}()
-	logger.Infof("🔄 Aster order sync started (interval: %v)", interval)
+func (t *AsterTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration, stop <-chan struct{}) {
+	syncloop.Run(stop, interval, "Aster", func() error {
+		return t.SyncOrdersFromAster(traderID, exchangeID, exchangeType, st)
+	})
 }

trader/auto_trader.go

@@ -421,7 +421,7 @@ func (at *AutoTrader) Run() error {
 	// Start Lighter order sync if using Lighter exchange
 	if at.exchange == "lighter" {
 		if lighterTrader, ok := at.trader.(*lighter.LighterTraderV2); ok && at.store != nil {
-			lighterTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second)
+			lighterTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second, at.stopMonitorCh)
 			at.logInfof("🔄 Lighter order+position sync enabled (every 30s)")
 		}
 	}
@@ -429,7 +429,7 @@ func (at *AutoTrader) Run() error {
 	// Start Hyperliquid order sync if using Hyperliquid exchange
 	if at.exchange == "hyperliquid" {
 		if hyperliquidTrader, ok := at.trader.(*hyperliquid.HyperliquidTrader); ok && at.store != nil {
-			hyperliquidTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second)
+			hyperliquidTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second, at.stopMonitorCh)
 			at.logInfof("🔄 Hyperliquid order+position sync enabled (every 30s)")
 		}
 	}
@@ -437,7 +437,7 @@ func (at *AutoTrader) Run() error {
 	// Start Bybit order sync if using Bybit exchange
 	if at.exchange == "bybit" {
 		if bybitTrader, ok := at.trader.(*bybit.BybitTrader); ok && at.store != nil {
-			bybitTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second)
+			bybitTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second, at.stopMonitorCh)
 			at.logInfof("🔄 Bybit order+position sync enabled (every 30s)")
 		}
 	}
@@ -445,7 +445,7 @@ func (at *AutoTrader) Run() error {
 	// Start OKX order sync if using OKX exchange
 	if at.exchange == "okx" {
 		if okxTrader, ok := at.trader.(*okx.OKXTrader); ok && at.store != nil {
-			okxTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second)
+			okxTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second, at.stopMonitorCh)
 			at.logInfof("🔄 OKX order+position sync enabled (every 30s)")
 		}
 	}
@@ -453,7 +453,7 @@ func (at *AutoTrader) Run() error {
 	// Start Bitget order sync if using Bitget exchange
 	if at.exchange == "bitget" {
 		if bitgetTrader, ok := at.trader.(*bitget.BitgetTrader); ok && at.store != nil {
-			bitgetTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second)
+			bitgetTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second, at.stopMonitorCh)
 			at.logInfof("🔄 Bitget order+position sync enabled (every 30s)")
 		}
 	}
@@ -461,7 +461,7 @@ func (at *AutoTrader) Run() error {
 	// Start Aster order sync if using Aster exchange
 	if at.exchange == "aster" {
 		if asterTrader, ok := at.trader.(*aster.AsterTrader); ok && at.store != nil {
-			asterTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second)
+			asterTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second, at.stopMonitorCh)
 			at.logInfof("🔄 Aster order+position sync enabled (every 30s)")
 		}
 	}
@@ -469,7 +469,7 @@ func (at *AutoTrader) Run() error {
 	// Start Binance order sync if using Binance exchange
 	if at.exchange == "binance" {
 		if binanceTrader, ok := at.trader.(*binance.FuturesTrader); ok && at.store != nil {
-			binanceTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second)
+			binanceTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second, at.stopMonitorCh)
 			at.logInfof("🔄 Binance order+position sync enabled (every 30s)")
 		}
 	}
@@ -477,7 +477,7 @@ func (at *AutoTrader) Run() error {
 	// Start Gate order sync if using Gate exchange
 	if at.exchange == "gate" {
 		if gateTrader, ok := at.trader.(*gate.GateTrader); ok && at.store != nil {
-			gateTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second)
+			gateTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second, at.stopMonitorCh)
 			at.logInfof("🔄 Gate order+position sync enabled (every 30s)")
 		}
 	}
@@ -485,7 +485,7 @@ func (at *AutoTrader) Run() error {
 	// Start KuCoin order sync if using KuCoin exchange
 	if at.exchange == "kucoin" {
 		if kucoinTrader, ok := at.trader.(*kucoin.KuCoinTrader); ok && at.store != nil {
-			kucoinTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second)
+			kucoinTrader.StartOrderSync(at.id, at.exchangeID, at.exchange, at.store, 30*time.Second, at.stopMonitorCh)
 			at.logInfof("🔄 KuCoin order+position sync enabled (every 30s)")
 		}
 	}

trader/binance/order_sync.go

@@ -5,6 +5,7 @@ import (
 	"nofx/logger"
 	"nofx/market"
 	"nofx/store"
+	"nofx/trader/syncloop"
 	"nofx/trader/types"
 	"sort"
 	"strings"
@@ -349,7 +350,7 @@ func (t *FuturesTrader) determineOrderAction(side, positionSide string, realized
 }
 
 // StartOrderSync starts background order sync task for Binance
-func (t *FuturesTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration) {
+func (t *FuturesTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration, stop <-chan struct{}) {
 	// Run first sync immediately
 	go func() {
 		logger.Infof("🔄 Running initial Binance order sync...")
@@ -359,13 +360,7 @@ func (t *FuturesTrader) StartOrderSync(traderID string, exchangeID string, excha
 	}()
 
 	// Then run periodically
-	ticker := time.NewTicker(interval)
-	go func() {
-		for range ticker.C {
-			if err := t.SyncOrdersFromBinance(traderID, exchangeID, exchangeType, st); err != nil {
-				logger.Infof("⚠️  Binance order sync failed: %v", err)
-			}
-		}
-	}()
-	logger.Infof("🔄 Binance order sync started (interval: %v)", interval)
+	syncloop.Run(stop, interval, "Binance", func() error {
+		return t.SyncOrdersFromBinance(traderID, exchangeID, exchangeType, st)
+	})
 }

trader/bitget/order_sync.go

@@ -6,6 +6,7 @@ import (
 	"nofx/logger"
 	"nofx/market"
 	"nofx/store"
+	"nofx/trader/syncloop"
 	"sort"
 	"strconv"
 	"strings"
@@ -48,7 +49,6 @@ func (t *BitgetTrader) GetTrades(startTime time.Time, limit int) ([]BitgetTrade,
 		return nil, fmt.Errorf("failed to get fill history: %w", err)
 	}
 
-
 	// Bitget fill structure - supports both one-way and hedge mode
 	type BitgetFill struct {
 		TradeID    string `json:"tradeId"`
@@ -279,14 +279,8 @@ func (t *BitgetTrader) SyncOrdersFromBitget(traderID string, exchangeID string,
 }
 
 // StartOrderSync starts background order sync task for Bitget
-func (t *BitgetTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration) {
-	ticker := time.NewTicker(interval)
-	go func() {
-		for range ticker.C {
-			if err := t.SyncOrdersFromBitget(traderID, exchangeID, exchangeType, st); err != nil {
-				logger.Infof("⚠️  Bitget order sync failed: %v", err)
-			}
-		}
-	}()
-	logger.Infof("🔄 Bitget order sync started (interval: %v)", interval)
+func (t *BitgetTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration, stop <-chan struct{}) {
+	syncloop.Run(stop, interval, "Bitget", func() error {
+		return t.SyncOrdersFromBitget(traderID, exchangeID, exchangeType, st)
+	})
 }

trader/bybit/order_sync.go

@@ -11,6 +11,7 @@ import (
 	"nofx/logger"
 	"nofx/market"
 	"nofx/store"
+	"nofx/trader/syncloop"
 	"sort"
 	"strconv"
 	"strings"
@@ -298,14 +299,8 @@ func (t *BybitTrader) SyncOrdersFromBybit(traderID string, exchangeID string, ex
 }
 
 // StartOrderSync starts background order sync task for Bybit
-func (t *BybitTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration) {
-	ticker := time.NewTicker(interval)
-	go func() {
-		for range ticker.C {
-			if err := t.SyncOrdersFromBybit(traderID, exchangeID, exchangeType, st); err != nil {
-				logger.Infof("⚠️  Bybit order sync failed: %v", err)
-			}
-		}
-	}()
-	logger.Infof("🔄 Bybit order sync started (interval: %v)", interval)
+func (t *BybitTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration, stop <-chan struct{}) {
+	syncloop.Run(stop, interval, "Bybit", func() error {
+		return t.SyncOrdersFromBybit(traderID, exchangeID, exchangeType, st)
+	})
 }

trader/gate/order_sync.go

@@ -5,6 +5,7 @@ import (
 	"nofx/logger"
 	"nofx/market"
 	"nofx/store"
+	"nofx/trader/syncloop"
 	"sort"
 	"strconv"
 	"strings"
@@ -291,14 +292,8 @@ func (t *GateTrader) SyncOrdersFromGate(traderID string, exchangeID string, exch
 }
 
 // StartOrderSync starts background order sync task for Gate
-func (t *GateTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration) {
-	ticker := time.NewTicker(interval)
-	go func() {
-		for range ticker.C {
-			if err := t.SyncOrdersFromGate(traderID, exchangeID, exchangeType, st); err != nil {
-				logger.Infof("⚠️  Gate order sync failed: %v", err)
-			}
-		}
-	}()
-	logger.Infof("🔄 Gate order sync started (interval: %v)", interval)
+func (t *GateTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration, stop <-chan struct{}) {
+	syncloop.Run(stop, interval, "Gate", func() error {
+		return t.SyncOrdersFromGate(traderID, exchangeID, exchangeType, st)
+	})
 }

trader/hyperliquid/order_sync.go

@@ -5,6 +5,7 @@ import (
 	"nofx/logger"
 	"nofx/market"
 	"nofx/store"
+	"nofx/trader/syncloop"
 	"sort"
 	"strings"
 	"time"
@@ -44,87 +45,87 @@ func (t *HyperliquidTrader) SyncOrdersFromHyperliquid(traderID string, exchangeI
 	syncedCount := 0
 
 	for _, trade := range trades {
-			// Check if trade already exists (use exchangeID which is UUID, not exchange type)
-			existing, err := orderStore.GetOrderByExchangeID(exchangeID, trade.TradeID)
-			if err == nil && existing != nil {
-				continue // Order already exists, skip
-			}
+		// Check if trade already exists (use exchangeID which is UUID, not exchange type)
+		existing, err := orderStore.GetOrderByExchangeID(exchangeID, trade.TradeID)
+		if err == nil && existing != nil {
+			continue // Order already exists, skip
+		}
 
-			// Normalize symbol
-			symbol := market.Normalize(trade.Symbol)
+		// Normalize symbol
+		symbol := market.Normalize(trade.Symbol)
 
-			// Use order action from trade (parsed from Hyperliquid Dir field)
-			// Dir field values: "Open Long", "Open Short", "Close Long", "Close Short"
-			orderAction := trade.OrderAction
-			positionSide := "LONG"
-			if strings.Contains(orderAction, "short") {
-				positionSide = "SHORT"
-			}
+		// Use order action from trade (parsed from Hyperliquid Dir field)
+		// Dir field values: "Open Long", "Open Short", "Close Long", "Close Short"
+		orderAction := trade.OrderAction
+		positionSide := "LONG"
+		if strings.Contains(orderAction, "short") {
+			positionSide = "SHORT"
+		}
 
-			// Create order record - use Unix milliseconds UTC
-			tradeTimeMs := trade.Time.UTC().UnixMilli()
-			orderRecord := &store.TraderOrder{
-				TraderID:        traderID,
-				ExchangeID:      exchangeID,   // UUID
-				ExchangeType:    exchangeType, // Exchange type
-				ExchangeOrderID: trade.TradeID,
-				Symbol:          symbol,
-				Side:            trade.Side,
-				PositionSide:    "BOTH", // Hyperliquid uses one-way position mode
-				Type:            "MARKET",
-				OrderAction:     orderAction,
-				Quantity:        trade.Quantity,
-				Price:           trade.Price,
-				Status:          "FILLED",
-				FilledQuantity:  trade.Quantity,
-				AvgFillPrice:    trade.Price,
-				Commission:      trade.Fee,
-				FilledAt:        tradeTimeMs,
-				CreatedAt:       tradeTimeMs,
-				UpdatedAt:       tradeTimeMs,
-			}
+		// Create order record - use Unix milliseconds UTC
+		tradeTimeMs := trade.Time.UTC().UnixMilli()
+		orderRecord := &store.TraderOrder{
+			TraderID:        traderID,
+			ExchangeID:      exchangeID,   // UUID
+			ExchangeType:    exchangeType, // Exchange type
+			ExchangeOrderID: trade.TradeID,
+			Symbol:          symbol,
+			Side:            trade.Side,
+			PositionSide:    "BOTH", // Hyperliquid uses one-way position mode
+			Type:            "MARKET",
+			OrderAction:     orderAction,
+			Quantity:        trade.Quantity,
+			Price:           trade.Price,
+			Status:          "FILLED",
+			FilledQuantity:  trade.Quantity,
+			AvgFillPrice:    trade.Price,
+			Commission:      trade.Fee,
+			FilledAt:        tradeTimeMs,
+			CreatedAt:       tradeTimeMs,
+			UpdatedAt:       tradeTimeMs,
+		}
 
-			// Insert order record
-			if err := orderStore.CreateOrder(orderRecord); err != nil {
-				logger.Infof("  ⚠️ Failed to sync trade %s: %v", trade.TradeID, err)
-				continue
-			}
+		// Insert order record
+		if err := orderStore.CreateOrder(orderRecord); err != nil {
+			logger.Infof("  ⚠️ Failed to sync trade %s: %v", trade.TradeID, err)
+			continue
+		}
 
-			// Create fill record - use Unix milliseconds UTC
-			fillRecord := &store.TraderFill{
-				TraderID:        traderID,
-				ExchangeID:      exchangeID,   // UUID
-				ExchangeType:    exchangeType, // Exchange type
-				OrderID:         orderRecord.ID,
-				ExchangeOrderID: trade.TradeID,
-				ExchangeTradeID: trade.TradeID,
-				Symbol:          symbol,
-				Side:            trade.Side,
-				Price:           trade.Price,
-				Quantity:        trade.Quantity,
-				QuoteQuantity:   trade.Price * trade.Quantity,
-				Commission:      trade.Fee,
-				CommissionAsset: "USDT",
-				RealizedPnL:     trade.RealizedPnL,
-				IsMaker:         false, // Hyperliquid GetTrades doesn't provide maker/taker info
-				CreatedAt:       tradeTimeMs,
-			}
+		// Create fill record - use Unix milliseconds UTC
+		fillRecord := &store.TraderFill{
+			TraderID:        traderID,
+			ExchangeID:      exchangeID,   // UUID
+			ExchangeType:    exchangeType, // Exchange type
+			OrderID:         orderRecord.ID,
+			ExchangeOrderID: trade.TradeID,
+			ExchangeTradeID: trade.TradeID,
+			Symbol:          symbol,
+			Side:            trade.Side,
+			Price:           trade.Price,
+			Quantity:        trade.Quantity,
+			QuoteQuantity:   trade.Price * trade.Quantity,
+			Commission:      trade.Fee,
+			CommissionAsset: "USDT",
+			RealizedPnL:     trade.RealizedPnL,
+			IsMaker:         false, // Hyperliquid GetTrades doesn't provide maker/taker info
+			CreatedAt:       tradeTimeMs,
+		}
 
-			if err := orderStore.CreateFill(fillRecord); err != nil {
-				logger.Infof("  ⚠️ Failed to sync fill for trade %s: %v", trade.TradeID, err)
-			}
+		if err := orderStore.CreateFill(fillRecord); err != nil {
+			logger.Infof("  ⚠️ Failed to sync fill for trade %s: %v", trade.TradeID, err)
+		}
 
-			// Create/update position record using PositionBuilder
-			if err := posBuilder.ProcessTrade(
-				traderID, exchangeID, exchangeType,
-				symbol, positionSide, orderAction,
-				trade.Quantity, trade.Price, trade.Fee, trade.RealizedPnL,
-				tradeTimeMs, trade.TradeID,
-			); err != nil {
-				logger.Infof("  ⚠️ Failed to sync position for trade %s: %v", trade.TradeID, err)
-			} else {
-				logger.Infof("  📍 Position updated for trade: %s (action: %s, qty: %.6f)", trade.TradeID, orderAction, trade.Quantity)
-			}
+		// Create/update position record using PositionBuilder
+		if err := posBuilder.ProcessTrade(
+			traderID, exchangeID, exchangeType,
+			symbol, positionSide, orderAction,
+			trade.Quantity, trade.Price, trade.Fee, trade.RealizedPnL,
+			tradeTimeMs, trade.TradeID,
+		); err != nil {
+			logger.Infof("  ⚠️ Failed to sync position for trade %s: %v", trade.TradeID, err)
+		} else {
+			logger.Infof("  📍 Position updated for trade: %s (action: %s, qty: %.6f)", trade.TradeID, orderAction, trade.Quantity)
+		}
 
 		syncedCount++
 		logger.Infof("  ✅ Synced trade: %s %s %s qty=%.6f price=%.6f pnl=%.2f fee=%.6f action=%s",
@@ -136,14 +137,8 @@ func (t *HyperliquidTrader) SyncOrdersFromHyperliquid(traderID string, exchangeI
 }
 
 // StartOrderSync starts background order sync task
-func (t *HyperliquidTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration) {
-	ticker := time.NewTicker(interval)
-	go func() {
-		for range ticker.C {
-			if err := t.SyncOrdersFromHyperliquid(traderID, exchangeID, exchangeType, st); err != nil {
-				logger.Infof("⚠️  Hyperliquid order sync failed: %v", err)
-			}
-		}
-	}()
-	logger.Infof("🔄 Hyperliquid order sync started (interval: %v)", interval)
+func (t *HyperliquidTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration, stop <-chan struct{}) {
+	syncloop.Run(stop, interval, "Hyperliquid", func() error {
+		return t.SyncOrdersFromHyperliquid(traderID, exchangeID, exchangeType, st)
+	})
 }

trader/kucoin/order_sync.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"nofx/logger"
 	"nofx/store"
+	"nofx/trader/syncloop"
 	"nofx/trader/types"
 	"sort"
 	"strings"
@@ -399,14 +400,8 @@ func (t *KuCoinTrader) SyncOrdersFromKuCoin(traderID string, exchangeID string,
 }
 
 // StartOrderSync starts background order sync task for KuCoin
-func (t *KuCoinTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration) {
-	ticker := time.NewTicker(interval)
-	go func() {
-		for range ticker.C {
-			if err := t.SyncOrdersFromKuCoin(traderID, exchangeID, exchangeType, st); err != nil {
-				logger.Infof("⚠️  KuCoin order sync failed: %v", err)
-			}
-		}
-	}()
-	logger.Infof("🔄 KuCoin order sync started (interval: %v)", interval)
+func (t *KuCoinTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration, stop <-chan struct{}) {
+	syncloop.Run(stop, interval, "KuCoin", func() error {
+		return t.SyncOrdersFromKuCoin(traderID, exchangeID, exchangeType, st)
+	})
 }

trader/lighter/order_sync.go

@@ -5,6 +5,7 @@ import (
 	"nofx/logger"
 	"nofx/market"
 	"nofx/store"
+	"nofx/trader/syncloop"
 	"sort"
 	"strings"
 	"time"
@@ -145,17 +146,14 @@ func (t *LighterTraderV2) SyncOrdersFromLighter(traderID string, exchangeID stri
 }
 
 // StartOrderSync starts background order sync task
-func (t *LighterTraderV2) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration) {
-	ticker := time.NewTicker(interval)
-	go func() {
-		for range ticker.C {
-			if err := t.SyncOrdersFromLighter(traderID, exchangeID, exchangeType, st); err != nil {
-				// Only log non-404 errors to reduce log spam
-				if !strings.Contains(err.Error(), "status 404") {
-					logger.Infof("⚠️  Order sync failed: %v", err)
-				}
-			}
+func (t *LighterTraderV2) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration, stop <-chan struct{}) {
+	syncloop.Run(stop, interval, "Lighter", func() error {
+		err := t.SyncOrdersFromLighter(traderID, exchangeID, exchangeType, st)
+		// A 404 just means the account has no fills yet — treat as a
+		// successful empty sync to avoid log spam and pointless backoff.
+		if err != nil && strings.Contains(err.Error(), "status 404") {
+			return nil
 		}
-	}()
-	logger.Infof("🔄 Lighter order+position sync started (interval: %v)", interval)
+		return err
+	})
 }

trader/okx/order_sync.go

@@ -6,6 +6,7 @@ import (
 	"nofx/logger"
 	"nofx/market"
 	"nofx/store"
+	"nofx/trader/syncloop"
 	"sort"
 	"strconv"
 	"strings"
@@ -272,14 +273,8 @@ func (t *OKXTrader) SyncOrdersFromOKX(traderID string, exchangeID string, exchan
 }
 
 // StartOrderSync starts background order sync task for OKX
-func (t *OKXTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration) {
-	ticker := time.NewTicker(interval)
-	go func() {
-		for range ticker.C {
-			if err := t.SyncOrdersFromOKX(traderID, exchangeID, exchangeType, st); err != nil {
-				logger.Infof("⚠️  OKX order sync failed: %v", err)
-			}
-		}
-	}()
-	logger.Infof("🔄 OKX order sync started (interval: %v)", interval)
+func (t *OKXTrader) StartOrderSync(traderID string, exchangeID string, exchangeType string, st *store.Store, interval time.Duration, stop <-chan struct{}) {
+	syncloop.Run(stop, interval, "OKX", func() error {
+		return t.SyncOrdersFromOKX(traderID, exchangeID, exchangeType, st)
+	})
 }

trader/syncloop/syncloop.go

@@ -0,0 +1,48 @@
+// Package syncloop runs background exchange order-sync loops with a shared
+// lifecycle: loops stop when the owning trader stops, and consecutive
+// failures back off exponentially so a rate-limiting exchange (HTTP 429)
+// is not hammered at full frequency.
+package syncloop
+
+import (
+	"time"
+
+	"nofx/logger"
+)
+
+// maxBackoff caps the failure backoff so a recovered exchange is picked up
+// within a few minutes at worst.
+const maxBackoff = 5 * time.Minute
+
+// Run starts a background loop calling syncFn at the given interval until
+// stop is closed. After each consecutive failure the wait doubles (capped at
+// maxBackoff); the first success resets it to the base interval.
+func Run(stop <-chan struct{}, interval time.Duration, name string, syncFn func() error) {
+	if interval <= 0 {
+		interval = 30 * time.Second
+	}
+	go func() {
+		wait := interval
+		timer := time.NewTimer(wait)
+		defer timer.Stop()
+		for {
+			select {
+			case <-stop:
+				logger.Infof("⏹ %s order sync stopped", name)
+				return
+			case <-timer.C:
+				if err := syncFn(); err != nil {
+					wait *= 2
+					if wait > maxBackoff {
+						wait = maxBackoff
+					}
+					logger.Infof("⚠️ %s order sync failed: %v (backing off, next attempt in %v)", name, err, wait)
+				} else {
+					wait = interval
+				}
+				timer.Reset(wait)
+			}
+		}
+	}()
+	logger.Infof("🔄 %s order sync started (interval: %v)", name, interval)
+}

trader/syncloop/syncloop_test.go

@@ -0,0 +1,78 @@
+package syncloop
+
+import (
+	"errors"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func TestRunStopsWhenStopChannelCloses(t *testing.T) {
+	stop := make(chan struct{})
+	var calls atomic.Int64
+
+	Run(stop, 5*time.Millisecond, "test", func() error {
+		calls.Add(1)
+		return nil
+	})
+
+	// Let a few ticks happen, then stop.
+	time.Sleep(30 * time.Millisecond)
+	close(stop)
+	time.Sleep(20 * time.Millisecond)
+	after := calls.Load()
+	if after == 0 {
+		t.Fatal("sync function never ran")
+	}
+
+	// No further calls after stop.
+	time.Sleep(40 * time.Millisecond)
+	if calls.Load() != after {
+		t.Fatalf("sync kept running after stop: %d -> %d", after, calls.Load())
+	}
+}
+
+func TestRunBacksOffOnConsecutiveFailures(t *testing.T) {
+	stop := make(chan struct{})
+	defer close(stop)
+	var calls atomic.Int64
+
+	Run(stop, 10*time.Millisecond, "test", func() error {
+		calls.Add(1)
+		return errors.New("API returned status 429")
+	})
+
+	// With a 10ms base interval and exponential backoff (10, 20, 40, 80...),
+	// 100ms allows at most ~4 failing attempts. Without backoff there would
+	// be ~10.
+	time.Sleep(100 * time.Millisecond)
+	got := calls.Load()
+	if got == 0 {
+		t.Fatal("sync function never ran")
+	}
+	if got > 5 {
+		t.Fatalf("expected backoff to throttle failing sync, got %d calls in 100ms", got)
+	}
+}
+
+func TestRunRecoversIntervalAfterSuccess(t *testing.T) {
+	stop := make(chan struct{})
+	defer close(stop)
+	var calls atomic.Int64
+
+	// Fail twice, then succeed forever.
+	Run(stop, 5*time.Millisecond, "test", func() error {
+		n := calls.Add(1)
+		if n <= 2 {
+			return errors.New("transient")
+		}
+		return nil
+	})
+
+	// Failures at 5ms and 15ms (backoff 10ms), success at ~35ms (backoff 20ms),
+	// then the interval resets to 5ms — plenty of successful runs by 150ms.
+	time.Sleep(150 * time.Millisecond)
+	if got := calls.Load(); got < 8 {
+		t.Fatalf("expected interval to reset after success, got only %d calls", got)
+	}
+}