diff --git a/pkg/backtest/report.go b/pkg/backtest/report.go
index 7cae8335a..0e1574280 100644
--- a/pkg/backtest/report.go
+++ b/pkg/backtest/report.go
@@ -35,6 +35,7 @@ type SummaryReport struct {
 	EndTime              time.Time        `json:"endTime"`
 	Sessions             []string         `json:"sessions"`
 	Symbols              []string         `json:"symbols"`
+	Intervals            []types.Interval `json:"intervals"`
 	InitialTotalBalances types.BalanceMap `json:"initialTotalBalances"`
 	FinalTotalBalances   types.BalanceMap `json:"finalTotalBalances"`
 
@@ -48,6 +49,8 @@ type SummaryReport struct {
 type SessionSymbolReport struct {
 	Exchange        types.ExchangeName        `json:"exchange"`
 	Symbol          string                    `json:"symbol,omitempty"`
+	Intervals       []types.Interval          `json:"intervals,omitempty"`
+	Subscriptions   []types.Subscription      `json:"subscriptions"`
 	Market          types.Market              `json:"market"`
 	LastPrice       fixedpoint.Value          `json:"lastPrice,omitempty"`
 	StartPrice      fixedpoint.Value          `json:"startPrice,omitempty"`
diff --git a/pkg/bbgo/smart_stops.go b/pkg/bbgo/smart_stops.go
index e3dd0ca26..7a17e1e38 100644
--- a/pkg/bbgo/smart_stops.go
+++ b/pkg/bbgo/smart_stops.go
@@ -52,7 +52,7 @@ func NewTrailingStopController(symbol string, config *TrailingStop) *TrailingSto
 
 func (c *TrailingStopController) Subscribe(session *ExchangeSession) {
 	session.Subscribe(types.KLineChannel, c.Symbol, types.SubscribeOptions{
-		Interval: c.Interval.String(),
+		Interval: c.Interval,
 	})
 }
 
diff --git a/pkg/cmd/backtest.go b/pkg/cmd/backtest.go
index 400f9fcbe..77ee77088 100644
--- a/pkg/cmd/backtest.go
+++ b/pkg/cmd/backtest.go
@@ -273,7 +273,8 @@ var BacktestCmd = &cobra.Command{
 			return err
 		}
 
-		exchangeSources, err := toExchangeSources(environ.Sessions())
+		backTestIntervals := []types.Interval{types.Interval1h, types.Interval1d}
+		exchangeSources, err := toExchangeSources(environ.Sessions(), backTestIntervals...)
 		if err != nil {
 			return err
 		}
@@ -468,7 +469,21 @@ var BacktestCmd = &cobra.Command{
 			Symbols:              nil,
 		}
 
+		allKLineIntervals := map[types.Interval]struct{}{}
 		for _, session := range environ.Sessions() {
+			for _, sub := range session.Subscriptions {
+				if sub.Channel == types.KLineChannel {
+					allKLineIntervals[types.Interval(sub.Options.Interval)] = struct{}{}
+				}
+			}
+		}
+
+		for interval := range allKLineIntervals {
+			summaryReport.Intervals = append(summaryReport.Intervals, interval)
+		}
+
+		for _, session := range environ.Sessions() {
+
 			for symbol, trades := range session.Trades {
 				symbolReport, err := createSymbolReport(userConfig, session, symbol, trades.Trades)
 				if err != nil {
@@ -551,6 +566,22 @@ func createSymbolReport(userConfig *bbgo.Config, session *bbgo.ExchangeSession,
 		FinalBalances:   finalBalances,
 		// Manifests:       manifests,
 	}
+
+	for _, s := range session.Subscriptions {
+		symbolReport.Subscriptions = append(symbolReport.Subscriptions, s)
+	}
+
+	sessionKLineIntervals := map[types.Interval]struct{}{}
+	for _, sub := range session.Subscriptions {
+		if sub.Channel == types.KLineChannel {
+			sessionKLineIntervals[types.Interval(sub.Options.Interval)] = struct{}{}
+		}
+	}
+
+	for interval := range sessionKLineIntervals {
+		symbolReport.Intervals = append(symbolReport.Intervals, interval)
+	}
+
 	return &symbolReport, nil
 }
 
@@ -586,12 +617,12 @@ func confirmation(s string) bool {
 	}
 }
 
-func toExchangeSources(sessions map[string]*bbgo.ExchangeSession) (exchangeSources []backtest.ExchangeDataSource, err error) {
+func toExchangeSources(sessions map[string]*bbgo.ExchangeSession, extraIntervals ...types.Interval) (exchangeSources []backtest.ExchangeDataSource, err error) {
 	for _, session := range sessions {
 		exchange := session.Exchange.(*backtest.Exchange)
 		exchange.InitMarketData()
 
-		c, err := exchange.SubscribeMarketData(types.Interval1h, types.Interval1d)
+		c, err := exchange.SubscribeMarketData(extraIntervals...)
 		if err != nil {
 			return exchangeSources, err
 		}
diff --git a/pkg/cmd/kline.go b/pkg/cmd/kline.go
index ccdeb7c89..7a346d0a3 100644
--- a/pkg/cmd/kline.go
+++ b/pkg/cmd/kline.go
@@ -56,7 +56,7 @@ var klineCmd = &cobra.Command{
 
 		s := session.Exchange.NewStream()
 		s.SetPublicOnly()
-		s.Subscribe(types.KLineChannel, symbol, types.SubscribeOptions{Interval: interval})
+		s.Subscribe(types.KLineChannel, symbol, types.SubscribeOptions{Interval: types.Interval(interval)})
 
 		s.OnKLineClosed(func(kline types.KLine) {
 			log.Infof("kline closed: %s", kline.String())
diff --git a/pkg/exchange/max/stream.go b/pkg/exchange/max/stream.go
index 385e24b04..d6d1e646c 100644
--- a/pkg/exchange/max/stream.go
+++ b/pkg/exchange/max/stream.go
@@ -92,7 +92,7 @@ func (s *Stream) handleConnect() {
 				Channel:    string(sub.Channel),
 				Market:     toLocalSymbol(sub.Symbol),
 				Depth:      depth,
-				Resolution: sub.Options.Interval,
+				Resolution: sub.Options.Interval.String(),
 			})
 		}
 
diff --git a/pkg/exchange/okex/convert.go b/pkg/exchange/okex/convert.go
index cb8a94f4a..fa70a1352 100644
--- a/pkg/exchange/okex/convert.go
+++ b/pkg/exchange/okex/convert.go
@@ -17,7 +17,7 @@ func toGlobalSymbol(symbol string) string {
 	return strings.ReplaceAll(symbol, "-", "")
 }
 
-////go:generate sh -c "echo \"package okex\nvar spotSymbolMap = map[string]string{\n\" $(curl -s -L 'https://okex.com/api/v5/public/instruments?instType=SPOT' | jq -r '.data[] | \"\\(.instId | sub(\"-\" ; \"\") | tojson ): \\( .instId | tojson),\n\"') \"\n}\" > symbols.go"
+// //go:generate sh -c "echo \"package okex\nvar spotSymbolMap = map[string]string{\n\" $(curl -s -L 'https://okex.com/api/v5/public/instruments?instType=SPOT' | jq -r '.data[] | \"\\(.instId | sub(\"-\" ; \"\") | tojson ): \\( .instId | tojson),\n\"') \"\n}\" > symbols.go"
 //go:generate go run gensymbols.go
 func toLocalSymbol(symbol string) string {
 	if s, ok := spotSymbolMap[symbol]; ok {
@@ -68,18 +68,19 @@ var CandleChannels = []string{
 	"candle30m", "candle15m", "candle5m", "candle3m", "candle1m",
 }
 
-func convertIntervalToCandle(interval string) string {
-	switch interval {
+func convertIntervalToCandle(interval types.Interval) string {
+	s := interval.String()
+	switch s {
 
 	case "1h", "2h", "4h", "6h", "12h", "1d", "3d":
-		return "candle" + strings.ToUpper(interval)
+		return "candle" + strings.ToUpper(s)
 
 	case "1m", "5m", "15m", "30m":
-		return "candle" + interval
+		return "candle" + s
 
 	}
 
-	return "candle" + interval
+	return "candle" + s
 }
 
 func convertSubscription(s types.Subscription) (WebsocketSubscription, error) {
@@ -270,7 +271,7 @@ func toGlobalOrderType(orderType okexapi.OrderType) (types.OrderType, error) {
 	return "", fmt.Errorf("unknown or unsupported okex order type: %s", orderType)
 }
 
-func toLocalInterval(src string, ) string {
+func toLocalInterval(src string) string {
 	var re = regexp.MustCompile("\\d+[hdw]")
 	return re.ReplaceAllStringFunc(src, func(w string) string {
 		return strings.ToUpper(w)
diff --git a/pkg/grpc/convert.go b/pkg/grpc/convert.go
index cce9e77cc..e8354cf1d 100644
--- a/pkg/grpc/convert.go
+++ b/pkg/grpc/convert.go
@@ -34,7 +34,7 @@ func toSubscriptions(sub *pb.Subscription) (types.Subscription, error) {
 			Symbol:  sub.Symbol,
 			Channel: types.KLineChannel,
 			Options: types.SubscribeOptions{
-				Interval: sub.Interval,
+				Interval: types.Interval(sub.Interval),
 			},
 		}, nil
 	}
diff --git a/pkg/strategy/bollgrid/strategy.go b/pkg/strategy/bollgrid/strategy.go
index f60440143..c657df16b 100644
--- a/pkg/strategy/bollgrid/strategy.go
+++ b/pkg/strategy/bollgrid/strategy.go
@@ -108,10 +108,10 @@ func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
 	}
 
 	// currently we need the 1m kline to update the last close price and indicators
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval.String()})
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval})
 
 	if len(s.RepostInterval) > 0 && s.Interval != s.RepostInterval {
-		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.RepostInterval.String()})
+		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.RepostInterval})
 	}
 }
 
diff --git a/pkg/strategy/bollmaker/strategy.go b/pkg/strategy/bollmaker/strategy.go
index be97db97a..f134ba107 100644
--- a/pkg/strategy/bollmaker/strategy.go
+++ b/pkg/strategy/bollmaker/strategy.go
@@ -185,18 +185,18 @@ func (s *Strategy) Initialize() error {
 
 func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
 	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{
-		Interval: string(s.Interval),
+		Interval: s.Interval,
 	})
 
 	if s.DefaultBollinger != nil && s.DefaultBollinger.Interval != "" {
 		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{
-			Interval: string(s.DefaultBollinger.Interval),
+			Interval: s.DefaultBollinger.Interval,
 		})
 	}
 
 	if s.NeutralBollinger != nil && s.NeutralBollinger.Interval != "" {
 		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{
-			Interval: string(s.NeutralBollinger.Interval),
+			Interval: s.NeutralBollinger.Interval,
 		})
 	}
 
diff --git a/pkg/strategy/emastop/strategy.go b/pkg/strategy/emastop/strategy.go
index 222430713..396568c8e 100644
--- a/pkg/strategy/emastop/strategy.go
+++ b/pkg/strategy/emastop/strategy.go
@@ -73,8 +73,8 @@ func (s *Strategy) ID() string {
 }
 
 func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval.String()})
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.MovingAverageInterval.String()})
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval})
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.MovingAverageInterval})
 }
 
 func (s *Strategy) CrossSubscribe(sessions map[string]*bbgo.ExchangeSession) {
@@ -83,7 +83,7 @@ func (s *Strategy) CrossSubscribe(sessions map[string]*bbgo.ExchangeSession) {
 
 	// make sure we have the connection alive
 	targetSession := sessions[s.TargetExchangeName]
-	targetSession.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval.String()})
+	targetSession.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval})
 }
 
 func (s *Strategy) clear(ctx context.Context, orderExecutor bbgo.OrderExecutor) {
diff --git a/pkg/strategy/ewoDgtrd/strategy.go b/pkg/strategy/ewoDgtrd/strategy.go
index 25d3a5888..4315e4fb0 100644
--- a/pkg/strategy/ewoDgtrd/strategy.go
+++ b/pkg/strategy/ewoDgtrd/strategy.go
@@ -81,8 +81,8 @@ func (s *Strategy) Initialize() error {
 
 func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
 	log.Infof("subscribe %s", s.Symbol)
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: types.Interval1m.String()})
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval.String()})
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: types.Interval1m})
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval})
 
 	session.Subscribe(types.BookTickerChannel, s.Symbol, types.SubscribeOptions{})
 
diff --git a/pkg/strategy/factorzoo/strategy.go b/pkg/strategy/factorzoo/strategy.go
index acc67c5ac..2cf131fdf 100644
--- a/pkg/strategy/factorzoo/strategy.go
+++ b/pkg/strategy/factorzoo/strategy.go
@@ -3,11 +3,13 @@ package factorzoo
 import (
 	"context"
 	"fmt"
+
+	"github.com/sajari/regression"
+	"github.com/sirupsen/logrus"
+
 	"github.com/c9s/bbgo/pkg/bbgo"
 	"github.com/c9s/bbgo/pkg/fixedpoint"
 	"github.com/c9s/bbgo/pkg/types"
-	"github.com/sajari/regression"
-	"github.com/sirupsen/logrus"
 )
 
 const ID = "factorzoo"
@@ -57,7 +59,7 @@ func (s *Strategy) ID() string {
 
 func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
 	log.Infof("subscribe %s", s.Symbol)
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval.String()})
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval})
 }
 
 func (s *Strategy) ClosePosition(ctx context.Context, percentage fixedpoint.Value) error {
@@ -85,7 +87,7 @@ func (s *Strategy) ClosePosition(ctx context.Context, percentage fixedpoint.Valu
 		Market:   s.Market,
 	}
 
-	//s.Notify("Submitting %s %s order to close position by %v", s.Symbol, side.String(), percentage, submitOrder)
+	// s.Notify("Submitting %s %s order to close position by %v", s.Symbol, side.String(), percentage, submitOrder)
 
 	createdOrders, err := s.session.Exchange.SubmitOrders(ctx, submitOrder)
 	if err != nil {
@@ -99,13 +101,13 @@ func (s *Strategy) ClosePosition(ctx context.Context, percentage fixedpoint.Valu
 
 func (s *Strategy) placeOrders(ctx context.Context, orderExecutor bbgo.OrderExecutor, er fixedpoint.Value) {
 
-	//if s.prevER.Sign() < 0 && er.Sign() > 0 {
+	// if s.prevER.Sign() < 0 && er.Sign() > 0 {
 	if er.Sign() >= 0 {
 		submitOrder := types.SubmitOrder{
 			Symbol:   s.Symbol,
 			Side:     types.SideTypeBuy,
 			Type:     types.OrderTypeMarket,
-			Quantity: s.Quantity, //er.Abs().Mul(fixedpoint.NewFromInt(20)),
+			Quantity: s.Quantity, // er.Abs().Mul(fixedpoint.NewFromInt(20)),
 		}
 		createdOrders, err := orderExecutor.SubmitOrders(ctx, submitOrder)
 		if err != nil {
@@ -113,13 +115,13 @@ func (s *Strategy) placeOrders(ctx context.Context, orderExecutor bbgo.OrderExec
 		}
 		s.orderStore.Add(createdOrders...)
 		s.activeMakerOrders.Add(createdOrders...)
-		//} else if s.prevER.Sign() > 0 && er.Sign() < 0 {
+		// } else if s.prevER.Sign() > 0 && er.Sign() < 0 {
 	} else {
 		submitOrder := types.SubmitOrder{
 			Symbol:   s.Symbol,
 			Side:     types.SideTypeSell,
 			Type:     types.OrderTypeMarket,
-			Quantity: s.Quantity, //er.Abs().Mul(fixedpoint.NewFromInt(20)),
+			Quantity: s.Quantity, // er.Abs().Mul(fixedpoint.NewFromInt(20)),
 		}
 		createdOrders, err := orderExecutor.SubmitOrders(ctx, submitOrder)
 		if err != nil {
@@ -144,13 +146,13 @@ func (s *Strategy) Run(ctx context.Context, orderExecutor bbgo.OrderExecutor, se
 	s.pvDivergence = &Correlation{IntervalWindow: iw}
 	// bind indicator to the data store, so that our callback could be triggered
 	s.pvDivergence.Bind(st)
-	//s.pvDivergence.OnUpdate(func(corr float64) {
+	// s.pvDivergence.OnUpdate(func(corr float64) {
 	//	//fmt.Printf("now we've got corr: %f\n", corr)
-	//})
+	// })
 
 	s.Alpha = [][]float64{{}, {}, {}, {}, {}}
 	s.Ret = []float64{}
-	//thetas := []float64{0, 0, 0, 0}
+	// thetas := []float64{0, 0, 0, 0}
 	preCompute := 0
 
 	s.activeMakerOrders = bbgo.NewLocalActiveOrderBook(s.Symbol)
@@ -198,7 +200,7 @@ func (s *Strategy) Run(ctx context.Context, orderExecutor bbgo.OrderExecutor, se
 		s.Alpha[3] = append(s.Alpha[3], mom.Float64())
 		s.Alpha[4] = append(s.Alpha[4], ogap.Float64())
 
-		//s.Alpha[5] = append(s.Alpha[4], 1.0) // constant
+		// s.Alpha[5] = append(s.Alpha[4], 1.0) // constant
 
 		ret := kline.Close.Sub(s.prevClose).Div(s.prevClose).Float64()
 		s.Ret = append(s.Ret, ret)
@@ -231,7 +233,7 @@ func (s *Strategy) Run(ctx context.Context, orderExecutor bbgo.OrderExecutor, se
 			r.Train(rdp...)
 			r.Run()
 			fmt.Printf("Regression formula:\n%v\n", r.Formula)
-			//prediction := r.Coeff(0)*corr.Float64() + r.Coeff(1)*rev.Float64() + r.Coeff(2)*factorzoo.Float64() + r.Coeff(3)*mom.Float64() + r.Coeff(4)
+			// prediction := r.Coeff(0)*corr.Float64() + r.Coeff(1)*rev.Float64() + r.Coeff(2)*factorzoo.Float64() + r.Coeff(3)*mom.Float64() + r.Coeff(4)
 			prediction, _ := r.Predict([]float64{corr.Float64(), rev.Float64(), a150.Float64(), mom.Float64(), ogap.Float64()})
 			log.Infof("Predicted Return: %f", prediction)
 
diff --git a/pkg/strategy/flashcrash/strategy.go b/pkg/strategy/flashcrash/strategy.go
index 662c3385f..58159c21e 100644
--- a/pkg/strategy/flashcrash/strategy.go
+++ b/pkg/strategy/flashcrash/strategy.go
@@ -106,7 +106,7 @@ func (s *Strategy) updateBidOrders(orderExecutor bbgo.OrderExecutor, session *bb
 }
 
 func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: string(s.Interval)})
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval})
 }
 
 func (s *Strategy) Run(ctx context.Context, orderExecutor bbgo.OrderExecutor, session *bbgo.ExchangeSession) error {
diff --git a/pkg/strategy/funding/strategy.go b/pkg/strategy/funding/strategy.go
index 937692577..2039eb54d 100644
--- a/pkg/strategy/funding/strategy.go
+++ b/pkg/strategy/funding/strategy.go
@@ -77,10 +77,10 @@ func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
 
 	for _, detection := range s.SupportDetection {
 		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{
-			Interval: string(detection.Interval),
+			Interval: detection.Interval,
 		})
 		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{
-			Interval: string(detection.MovingAverageIntervalWindow.Interval),
+			Interval: detection.MovingAverageIntervalWindow.Interval,
 		})
 	}
 }
diff --git a/pkg/strategy/kline/strategy.go b/pkg/strategy/kline/strategy.go
index 1dae69be4..2c800efaa 100644
--- a/pkg/strategy/kline/strategy.go
+++ b/pkg/strategy/kline/strategy.go
@@ -2,6 +2,7 @@ package kline
 
 import (
 	"context"
+
 	"github.com/sirupsen/logrus"
 
 	"github.com/c9s/bbgo/pkg/bbgo"
@@ -26,7 +27,7 @@ func (s *Strategy) ID() string {
 }
 
 func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: string(s.MovingAverage.Interval)})
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.MovingAverage.Interval})
 }
 
 func (s *Strategy) Run(ctx context.Context, orderExecutor bbgo.OrderExecutor, session *bbgo.ExchangeSession) error {
diff --git a/pkg/strategy/pivotshort/strategy.go b/pkg/strategy/pivotshort/strategy.go
index 692b8ae76..6976ee4d8 100644
--- a/pkg/strategy/pivotshort/strategy.go
+++ b/pkg/strategy/pivotshort/strategy.go
@@ -3,6 +3,7 @@ package pivotshort
 import (
 	"context"
 	"fmt"
+
 	"github.com/c9s/bbgo/pkg/bbgo"
 	"github.com/c9s/bbgo/pkg/fixedpoint"
 	"github.com/c9s/bbgo/pkg/indicator"
@@ -65,9 +66,8 @@ func (s *Strategy) ID() string {
 
 func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
 	log.Infof("subscribe %s", s.Symbol)
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval.String()})
-	//session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: types.Interval1d.String()})
-
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval})
+	//session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: types.Interval1d})
 }
 
 func (s *Strategy) placeOrder(ctx context.Context, price fixedpoint.Value, qty fixedpoint.Value, orderExecutor bbgo.OrderExecutor) {
diff --git a/pkg/strategy/pricealert/strategy.go b/pkg/strategy/pricealert/strategy.go
index 0e484e52b..a9b5dcc30 100644
--- a/pkg/strategy/pricealert/strategy.go
+++ b/pkg/strategy/pricealert/strategy.go
@@ -20,7 +20,7 @@ type Strategy struct {
 
 	// These fields will be filled from the config file (it translates YAML to JSON)
 	Symbol    string           `json:"symbol"`
-	Interval  string           `json:"interval"`
+	Interval  types.Interval   `json:"interval"`
 	MinChange fixedpoint.Value `json:"minChange"`
 }
 
diff --git a/pkg/strategy/pricedrop/strategy.go b/pkg/strategy/pricedrop/strategy.go
index 915f7b59c..bfca2577f 100644
--- a/pkg/strategy/pricedrop/strategy.go
+++ b/pkg/strategy/pricedrop/strategy.go
@@ -35,7 +35,7 @@ func (s *Strategy) ID() string {
 }
 
 func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: string(s.Interval)})
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval})
 }
 
 func (s *Strategy) Run(ctx context.Context, orderExecutor bbgo.OrderExecutor, session *bbgo.ExchangeSession) error {
diff --git a/pkg/strategy/rebalance/strategy.go b/pkg/strategy/rebalance/strategy.go
index 64d1c6d5a..e9eb0bc50 100644
--- a/pkg/strategy/rebalance/strategy.go
+++ b/pkg/strategy/rebalance/strategy.go
@@ -74,7 +74,7 @@ func (s *Strategy) Validate() error {
 
 func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
 	for _, symbol := range s.getSymbols() {
-		session.Subscribe(types.KLineChannel, symbol, types.SubscribeOptions{Interval: s.Interval.String()})
+		session.Subscribe(types.KLineChannel, symbol, types.SubscribeOptions{Interval: s.Interval})
 	}
 }
 
diff --git a/pkg/strategy/schedule/strategy.go b/pkg/strategy/schedule/strategy.go
index 4d34263b9..00aa10a46 100644
--- a/pkg/strategy/schedule/strategy.go
+++ b/pkg/strategy/schedule/strategy.go
@@ -46,12 +46,12 @@ func (s *Strategy) ID() string {
 }
 
 func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval.String()})
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval})
 	if s.BelowMovingAverage != nil {
-		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.BelowMovingAverage.Interval.String()})
+		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.BelowMovingAverage.Interval})
 	}
 	if s.AboveMovingAverage != nil {
-		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.AboveMovingAverage.Interval.String()})
+		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.AboveMovingAverage.Interval})
 	}
 }
 
diff --git a/pkg/strategy/support/strategy.go b/pkg/strategy/support/strategy.go
index 91aaeabdd..83768c56b 100644
--- a/pkg/strategy/support/strategy.go
+++ b/pkg/strategy/support/strategy.go
@@ -202,14 +202,14 @@ func (s *Strategy) Validate() error {
 }
 
 func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
-	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: string(s.Interval)})
+	session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.Interval})
 
 	if s.TriggerMovingAverage != zeroiw {
-		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: string(s.TriggerMovingAverage.Interval)})
+		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.TriggerMovingAverage.Interval})
 	}
 
 	if s.LongTermMovingAverage != zeroiw {
-		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: string(s.LongTermMovingAverage.Interval)})
+		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{Interval: s.LongTermMovingAverage.Interval})
 	}
 }
 
diff --git a/pkg/strategy/swing/strategy.go b/pkg/strategy/swing/strategy.go
index 2d8d9e55b..bd087731e 100644
--- a/pkg/strategy/swing/strategy.go
+++ b/pkg/strategy/swing/strategy.go
@@ -55,7 +55,7 @@ type Strategy struct {
 
 	// Interval is the interval of the kline channel we want to subscribe,
 	// the kline event will trigger the strategy to check if we need to submit order.
-	Interval string `json:"interval"`
+	Interval types.Interval `json:"interval"`
 
 	// MinChange filters out the k-lines with small changes. so that our strategy will only be triggered
 	// in specific events.
diff --git a/pkg/strategy/techsignal/strategy.go b/pkg/strategy/techsignal/strategy.go
index 814af8474..ac1e5145e 100644
--- a/pkg/strategy/techsignal/strategy.go
+++ b/pkg/strategy/techsignal/strategy.go
@@ -7,9 +7,10 @@ import (
 	"strings"
 	"time"
 
+	"github.com/sirupsen/logrus"
+
 	"github.com/c9s/bbgo/pkg/exchange/binance"
 	"github.com/c9s/bbgo/pkg/fixedpoint"
-	"github.com/sirupsen/logrus"
 
 	"github.com/c9s/bbgo/pkg/bbgo"
 	"github.com/c9s/bbgo/pkg/types"
@@ -69,11 +70,11 @@ func (s *Strategy) Subscribe(session *bbgo.ExchangeSession) {
 	// session.Subscribe(types.BookChannel, s.Symbol, types.SubscribeOptions{})
 	for _, detection := range s.SupportDetection {
 		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{
-			Interval: string(detection.Interval),
+			Interval: detection.Interval,
 		})
 
 		session.Subscribe(types.KLineChannel, s.Symbol, types.SubscribeOptions{
-			Interval: string(detection.MovingAverageInterval),
+			Interval: detection.MovingAverageInterval,
 		})
 	}
 }
diff --git a/pkg/types/stream.go b/pkg/types/stream.go
index a45a2d3fc..2363bb215 100644
--- a/pkg/types/stream.go
+++ b/pkg/types/stream.go
@@ -410,14 +410,14 @@ const (
 // SubscribeOptions provides the standard stream options
 type SubscribeOptions struct {
 	// TODO: change to Interval type later
-	Interval string `json:"interval,omitempty"`
-	Depth    Depth  `json:"depth,omitempty"`
-	Speed    Speed  `json:"speed,omitempty"`
+	Interval Interval `json:"interval,omitempty"`
+	Depth    Depth    `json:"depth,omitempty"`
+	Speed    Speed    `json:"speed,omitempty"`
 }
 
 func (o SubscribeOptions) String() string {
 	if len(o.Interval) > 0 {
-		return o.Interval
+		return string(o.Interval)
 	}
 
 	return string(o.Depth)