diff --git a/pkg/backtest/exchange.go b/pkg/backtest/exchange.go
index db24d44a9..12b214156 100644
--- a/pkg/backtest/exchange.go
+++ b/pkg/backtest/exchange.go
@@ -25,7 +25,7 @@ type Exchange struct {
 	account *types.Account
 	config  *bbgo.Backtest
 
-	stream *Stream
+	userDataStream *Stream
 
 	trades        map[string][]types.Trade
 	closedOrders  map[string][]types.Order
@@ -91,31 +91,7 @@ func (e *Exchange) Done() chan struct{} {
 }
 
 func (e *Exchange) NewStream() types.Stream {
-	if e.stream != nil {
-		panic("backtest stream can not be allocated twice")
-	}
-
-	e.stream = &Stream{exchange: e}
-
-	e.stream.OnTradeUpdate(func(trade types.Trade) {
-		e.trades[trade.Symbol] = append(e.trades[trade.Symbol], trade)
-	})
-
-	for symbol, market := range e.markets {
-		matching := &SimplePriceMatching{
-			CurrentTime:     e.startTime,
-			Account:         e.account,
-			Market:          market,
-			MakerCommission: e.config.Account.MakerCommission,
-			TakerCommission: e.config.Account.TakerCommission,
-		}
-		matching.OnTradeUpdate(e.stream.EmitTradeUpdate)
-		matching.OnOrderUpdate(e.stream.EmitOrderUpdate)
-		matching.OnBalanceUpdate(e.stream.EmitBalanceUpdate)
-		e.matchingBooks[symbol] = matching
-	}
-
-	return e.stream
+	return &Stream{exchange: e}
 }
 
 func (e Exchange) SubmitOrders(ctx context.Context, orders ...types.SubmitOrder) (createdOrders types.OrderSlice, err error) {
@@ -140,11 +116,11 @@ func (e Exchange) SubmitOrders(ctx context.Context, orders ...types.SubmitOrder)
 				e.closedOrders[symbol] = append(e.closedOrders[symbol], *createdOrder)
 			}
 
-			e.stream.EmitOrderUpdate(*createdOrder)
+			e.userDataStream.EmitOrderUpdate(*createdOrder)
 		}
 
 		if trade != nil {
-			e.stream.EmitTradeUpdate(*trade)
+			e.userDataStream.EmitTradeUpdate(*trade)
 		}
 	}
 
@@ -180,7 +156,7 @@ func (e Exchange) CancelOrders(ctx context.Context, orders ...types.Order) error
 			return err
 		}
 
-		e.stream.EmitOrderUpdate(canceledOrder)
+		e.userDataStream.EmitOrderUpdate(canceledOrder)
 	}
 
 	return nil
diff --git a/pkg/backtest/stream.go b/pkg/backtest/stream.go
index f920fb1de..01169a4b5 100644
--- a/pkg/backtest/stream.go
+++ b/pkg/backtest/stream.go
@@ -15,6 +15,8 @@ type Stream struct {
 	types.StandardStream
 
 	exchange *Exchange
+
+	publicOnly bool
 }
 
 func (s *Stream) Connect(ctx context.Context) error {
@@ -51,48 +53,72 @@ func (s *Stream) Connect(ctx context.Context) error {
 
 	log.Infof("used symbols: %v and intervals: %v", symbols, intervals)
 
-	go func() {
-		log.Infof("emitting connect callbacks...")
-		s.EmitConnect()
+	if !s.publicOnly {
+		// user data stream
+		s.OnTradeUpdate(func(trade types.Trade) {
+			s.exchange.trades[trade.Symbol] = append(s.exchange.trades[trade.Symbol], trade)
+		})
 
-		log.Infof("emitting start callbacks...")
-		s.EmitStart()
+		for symbol, market := range s.exchange.markets {
+			matching := &SimplePriceMatching{
+				CurrentTime:     s.exchange.startTime,
+				Account:         s.exchange.account,
+				Market:          market,
+				MakerCommission: s.exchange.config.Account.MakerCommission,
+				TakerCommission: s.exchange.config.Account.TakerCommission,
+			}
+			matching.OnTradeUpdate(s.EmitTradeUpdate)
+			matching.OnOrderUpdate(s.EmitOrderUpdate)
+			matching.OnBalanceUpdate(s.EmitBalanceUpdate)
+			s.exchange.matchingBooks[symbol] = matching
+		}
 
-		log.Infof("querying klines from database...")
-		klineC, errC := s.exchange.srv.QueryKLinesCh(s.exchange.startTime, s.exchange.endTime, s.exchange, symbols, intervals)
-		numKlines := 0
-		for k := range klineC {
-			if k.Interval == types.Interval1m {
-				matching, ok := s.exchange.matchingBooks[k.Symbol]
-				if !ok {
-					log.Errorf("matching book of %s is not initialized", k.Symbol)
-					continue
+		// assign user data stream back
+		s.exchange.userDataStream = s
+	}
+
+	s.EmitConnect()
+	s.EmitStart()
+
+	if s.publicOnly {
+		go func() {
+			log.Infof("querying klines from database...")
+			klineC, errC := s.exchange.srv.QueryKLinesCh(s.exchange.startTime, s.exchange.endTime, s.exchange, symbols, intervals)
+			numKlines := 0
+			for k := range klineC {
+				if k.Interval == types.Interval1m {
+					matching, ok := s.exchange.matchingBooks[k.Symbol]
+					if !ok {
+						log.Errorf("matching book of %s is not initialized", k.Symbol)
+						continue
+					}
+
+					matching.processKLine(k)
+					numKlines++
 				}
 
-				matching.processKLine(k)
-				numKlines++
+				s.EmitKLineClosed(k)
 			}
 
-			s.EmitKLineClosed(k)
-		}
+			if err := <-errC; err != nil {
+				log.WithError(err).Error("backtest data feed error")
+			}
 
-		if err := <-errC; err != nil {
-			log.WithError(err).Error("backtest data feed error")
-		}
+			if numKlines == 0 {
+				log.Error("kline data is empty, make sure you have sync the exchange market data")
+			}
 
-		if numKlines == 0 {
-			log.Error("kline data is empty, make sure you have sync the exchange market data")
-		}
-
-		if err := s.Close(); err != nil {
-			log.WithError(err).Error("stream close error")
-		}
-	}()
+			if err := s.Close(); err != nil {
+				log.WithError(err).Error("stream close error")
+			}
+		}()
+	}
 
 	return nil
 }
 
 func (s *Stream) SetPublicOnly() {
+	s.publicOnly = true
 	return
 }
 
diff --git a/pkg/bbgo/environment.go b/pkg/bbgo/environment.go
index ef4848c47..37784ca2e 100644
--- a/pkg/bbgo/environment.go
+++ b/pkg/bbgo/environment.go
@@ -211,11 +211,8 @@ func (environ *Environment) AddExchangesByViperKeys() error {
 }
 
 func InitExchangeSession(name string, session *ExchangeSession) error {
-	exchangeName, err := types.ValidExchangeName(session.ExchangeName)
-	if err != nil {
-		return err
-	}
-
+	var err error
+	var exchangeName = session.ExchangeName
 	var exchange types.Exchange
 	if session.Key != "" && session.Secret != "" {
 		if !session.PublicOnly {
diff --git a/pkg/server/routes.go b/pkg/server/routes.go
index 878a0cc79..d428f0270 100644
--- a/pkg/server/routes.go
+++ b/pkg/server/routes.go
@@ -133,7 +133,7 @@ func (s *Server) newEngine() *gin.Engine {
 			return
 		}
 
-		err := bbgo.InitExchangeSession(session.ExchangeName, &session)
+		err := bbgo.InitExchangeSession(session.ExchangeName.String(), &session)
 		if err != nil {
 			c.JSON(http.StatusInternalServerError, gin.H{
 				"error": err.Error(),
@@ -182,7 +182,7 @@ func (s *Server) newEngine() *gin.Engine {
 			return
 		}
 
-		if err := bbgo.InitExchangeSession(session.ExchangeName, &session); err != nil {
+		if err := bbgo.InitExchangeSession(session.ExchangeName.String(), &session); err != nil {
 			c.JSON(http.StatusInternalServerError, gin.H{
 				"error": err.Error(),
 			})