diff --git a/pkg/bbgo/sync.go b/pkg/bbgo/sync.go
deleted file mode 100644
index 0f9a7ea3a..000000000
--- a/pkg/bbgo/sync.go
+++ /dev/null
@@ -1,91 +0,0 @@
-package bbgo
-
-import (
-	"context"
-	"time"
-
-	"github.com/sirupsen/logrus"
-)
-
-func stringSliceContains(slice []string, needle string) bool {
-	for _, s := range slice {
-		if s == needle {
-			return true
-		}
-	}
-
-	return false
-}
-
-func FindPossibleSymbols(session *ExchangeSession) (symbols []string, err error) {
-	var balances = session.Account.Balances()
-	var fiatCurrencies = []string{"USDC", "USDT", "USD", "TWD", "EUR", "GBP"}
-	var fiatAssets []string
-
-	for _, currency := range fiatCurrencies {
-		if balance, ok := balances[currency]; ok && balance.Total() > 0 {
-			fiatAssets = append(fiatAssets, currency)
-		}
-	}
-
-	var symbolMap = map[string]struct{}{}
-
-	for _, market := range session.Markets() {
-		// ignore the markets that are not fiat currency markets
-		if !stringSliceContains(fiatAssets, market.QuoteCurrency) {
-			continue
-		}
-
-		// ignore the asset that we don't have in the balance sheet
-		balance, hasAsset := balances[market.BaseCurrency]
-		if !hasAsset || balance.Total() == 0 {
-			continue
-		}
-
-		symbolMap[market.Symbol] = struct{}{}
-	}
-
-	for s := range symbolMap {
-		symbols = append(symbols, s)
-	}
-
-	return symbols, nil
-}
-
-// SyncSessionSymbols syncs the trades from the given exchange session
-func SyncSessionSymbols(ctx context.Context, environ *Environment, session *ExchangeSession, startTime time.Time, symbols ...string) error {
-	for _, symbol := range symbols {
-		logrus.Debugf("syncing trades from exchange session %s...", session.Name)
-		if err := environ.TradeSync.SyncTrades(ctx, session.Exchange, symbol, startTime); err != nil {
-			return err
-		}
-
-		logrus.Debugf("syncing orders from exchange session %s...", session.Name)
-		if err := environ.TradeSync.SyncOrders(ctx, session.Exchange, symbol, startTime); err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
-
-func getSessionSymbols(session *ExchangeSession, defaultSymbols ...string) ([]string, error) {
-	if session.IsolatedMargin {
-		return []string{session.IsolatedMarginSymbol}, nil
-	}
-
-	if len(defaultSymbols) > 0 {
-		return defaultSymbols, nil
-	}
-
-	return FindPossibleSymbols(session)
-}
-
-func SyncSession(ctx context.Context, environ *Environment, session *ExchangeSession, startTime time.Time, defaultSymbols ...string) error {
-	symbols, err := getSessionSymbols(session, defaultSymbols...)
-	if err != nil {
-		return err
-	}
-
-	return SyncSessionSymbols(ctx, environ, session, startTime, symbols...)
-}
diff --git a/pkg/cmd/sync.go b/pkg/cmd/sync.go
index 2406b2837..c21c92cf1 100644
--- a/pkg/cmd/sync.go
+++ b/pkg/cmd/sync.go
@@ -102,7 +102,7 @@ var SyncCmd = &cobra.Command{
 				return err
 			}
 
-			if err := bbgo.SyncSession(ctx, environ, session, startTime, defaultSymbols...) ; err != nil {
+			if err := environ.TradeSync.SyncSession(ctx, session, startTime, defaultSymbols...) ; err != nil {
 				return err
 			}
 
diff --git a/pkg/service/sync.go b/pkg/service/sync.go
index f83ed2a5e..2c7c2b2c6 100644
--- a/pkg/service/sync.go
+++ b/pkg/service/sync.go
@@ -6,6 +6,7 @@ import (
 
 	"github.com/sirupsen/logrus"
 
+	"github.com/c9s/bbgo/pkg/bbgo"
 	batch2 "github.com/c9s/bbgo/pkg/exchange/batch"
 	"github.com/c9s/bbgo/pkg/types"
 )
@@ -131,3 +132,89 @@ func (s *SyncService) SyncTrades(ctx context.Context, exchange types.Exchange, s
 
 	return <-errC
 }
+
+
+// SyncSessionSymbols syncs the trades from the given exchange session
+func (s *SyncService) SyncSessionSymbols(ctx context.Context, session *bbgo.ExchangeSession, startTime time.Time, symbols ...string) error {
+	for _, symbol := range symbols {
+		logrus.Debugf("syncing trades from exchange session %s...", session.Name)
+		if err := s.SyncTrades(ctx, session.Exchange, symbol, startTime); err != nil {
+			return err
+		}
+
+		logrus.Debugf("syncing orders from exchange session %s...", session.Name)
+		if err := s.SyncOrders(ctx, session.Exchange, symbol, startTime); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (s *SyncService) SyncSession(ctx context.Context, session *bbgo.ExchangeSession, startTime time.Time, defaultSymbols ...string) error {
+	symbols, err := getSessionSymbols(session, defaultSymbols...)
+	if err != nil {
+		return err
+	}
+
+	return s.SyncSessionSymbols(ctx, session, startTime, symbols...)
+}
+
+func getSessionSymbols(session *bbgo.ExchangeSession, defaultSymbols ...string) ([]string, error) {
+	if session.IsolatedMargin {
+		return []string{session.IsolatedMarginSymbol}, nil
+	}
+
+	if len(defaultSymbols) > 0 {
+		return defaultSymbols, nil
+	}
+
+	return FindPossibleSymbols(session)
+}
+
+
+func FindPossibleSymbols(session *bbgo.ExchangeSession) (symbols []string, err error) {
+	var balances = session.Account.Balances()
+	var fiatCurrencies = []string{"USDC", "USDT", "USD", "TWD", "EUR", "GBP"}
+	var fiatAssets []string
+
+	for _, currency := range fiatCurrencies {
+		if balance, ok := balances[currency]; ok && balance.Total() > 0 {
+			fiatAssets = append(fiatAssets, currency)
+		}
+	}
+
+	var symbolMap = map[string]struct{}{}
+
+	for _, market := range session.Markets() {
+		// ignore the markets that are not fiat currency markets
+		if !stringSliceContains(fiatAssets, market.QuoteCurrency) {
+			continue
+		}
+
+		// ignore the asset that we don't have in the balance sheet
+		balance, hasAsset := balances[market.BaseCurrency]
+		if !hasAsset || balance.Total() == 0 {
+			continue
+		}
+
+		symbolMap[market.Symbol] = struct{}{}
+	}
+
+	for s := range symbolMap {
+		symbols = append(symbols, s)
+	}
+
+	return symbols, nil
+}
+
+
+func stringSliceContains(slice []string, needle string) bool {
+	for _, s := range slice {
+		if s == needle {
+			return true
+		}
+	}
+
+	return false
+}