diff --git a/examples/interact/main.go b/examples/interact/main.go
index 248b8ff19..67308b2a8 100644
--- a/examples/interact/main.go
+++ b/examples/interact/main.go
@@ -128,7 +128,7 @@ func main() {
 	}
 
 	ctx := context.Background()
-	interact.SetMessenger(&interact.Telegram{
+	interact.AddMessenger(&interact.Telegram{
 		Private: true,
 		Bot:     b,
 	})
diff --git a/go.mod b/go.mod
index 7eace2ffb..84cb1f7f0 100644
--- a/go.mod
+++ b/go.mod
@@ -43,7 +43,7 @@ require (
 	github.com/robfig/cron/v3 v3.0.0
 	github.com/shopspring/decimal v1.2.0 // indirect
 	github.com/sirupsen/logrus v1.8.1
-	github.com/slack-go/slack v0.6.6-0.20200602212211-b04b8521281b
+	github.com/slack-go/slack v0.10.1
 	github.com/spf13/afero v1.5.1 // indirect
 	github.com/spf13/cast v1.3.1 // indirect
 	github.com/spf13/cobra v1.1.1
diff --git a/go.sum b/go.sum
index a3fa25afb..c2a503692 100644
--- a/go.sum
+++ b/go.sum
@@ -415,6 +415,8 @@ github.com/sirupsen/logrus v1.8.1 h1:dJKuHgqk1NNQlqoA6BTlM1Wf9DOH3NBjQyu0h9+AZZE
 github.com/sirupsen/logrus v1.8.1/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic61uBYv0=
 github.com/slack-go/slack v0.6.6-0.20200602212211-b04b8521281b h1:4NIpokK7Rg/k6lSzNQzvGLphpHtfAAaLw9AWHxHQn0w=
 github.com/slack-go/slack v0.6.6-0.20200602212211-b04b8521281b/go.mod h1:FGqNzJBmxIsZURAxh2a8D21AnOVvvXZvGligs4npPUM=
+github.com/slack-go/slack v0.10.1 h1:BGbxa0kMsGEvLOEoZmYs8T1wWfoZXwmQFBb6FgYCXUA=
+github.com/slack-go/slack v0.10.1/go.mod h1:wWL//kk0ho+FcQXcBTmEafUI5dz4qz5f4mMk8oIkioQ=
 github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d h1:zE9ykElWQ6/NYmHa3jpm/yHnI4xSofP+UP6SpjHcSeM=
 github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc=
 github.com/smartystreets/goconvey v1.6.4 h1:fv0U8FUIMPNf1L9lnHLvLhgicrIVChEkdzIKYqbNC9s=
diff --git a/pkg/bbgo/environment.go b/pkg/bbgo/environment.go
index c6290c5f5..d4580e2bc 100644
--- a/pkg/bbgo/environment.go
+++ b/pkg/bbgo/environment.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"image/png"
 	"io/ioutil"
+	stdlog "log"
 	"math/rand"
 	"os"
 	"strings"
@@ -16,6 +17,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/pquerna/otp"
 	log "github.com/sirupsen/logrus"
+	"github.com/slack-go/slack"
 	"github.com/spf13/viper"
 	"gopkg.in/tucnak/telebot.v2"
 
@@ -575,7 +577,7 @@ func (environ *Environment) ConfigureNotificationSystem(userConfig *Config) erro
 	// setup slack
 	slackToken := viper.GetString("slack-token")
 	if len(slackToken) > 0 && userConfig.Notifications != nil {
-		environ.setupSlack(userConfig, slackToken)
+		environ.setupSlack(userConfig, slackToken, persistence)
 	}
 
 	// check if telegram bot token is defined
@@ -672,18 +674,65 @@ func (environ *Environment) getAuthStore(persistence service.PersistenceService)
 	return persistence.NewStore("bbgo", "auth", id)
 }
 
-func (environ *Environment) setupSlack(userConfig *Config, slackToken string) {
-	if conf := userConfig.Notifications.Slack; conf != nil {
-		if conf.ErrorChannel != "" {
-			log.Debugf("found slack configured, setting up log hook...")
-			log.AddHook(slacklog.NewLogHook(slackToken, conf.ErrorChannel))
+func (environ *Environment) setupSlack(userConfig *Config, slackToken string, persistence service.PersistenceService) {
+
+	conf := userConfig.Notifications.Slack
+	if conf == nil {
+		return
+	}
+
+	if !strings.HasPrefix(slackToken, "xoxb-") {
+		log.Error("SLACK_BOT_TOKEN must have the prefix \"xoxb-\".")
+		return
+	}
+
+	// app-level token (for specific api)
+	slackAppToken := viper.GetString("slack-app-token")
+	if !strings.HasPrefix(slackAppToken, "xapp-") {
+		log.Errorf("SLACK_APP_TOKEN must have the prefix \"xapp-\".")
+		return
+	}
+
+	if conf.ErrorChannel != "" {
+		log.Debugf("found slack configured, setting up log hook...")
+		log.AddHook(slacklog.NewLogHook(slackToken, conf.ErrorChannel))
+	}
+
+	log.Debugf("adding slack notifier with default channel: %s", conf.DefaultChannel)
+
+	var client = slack.New(slackToken,
+		slack.OptionDebug(true),
+		slack.OptionLog(stdlog.New(os.Stdout, "api: ", stdlog.Lshortfile|stdlog.LstdFlags)),
+		slack.OptionAppLevelToken(slackAppToken))
+
+	var notifier = slacknotifier.New(client, conf.DefaultChannel)
+	environ.AddNotifier(notifier)
+
+	// allocate a store, so that we can save the chatID for the owner
+	var messenger = interact.NewSlack(client)
+
+	var sessions = interact.SlackSessionMap{}
+	var sessionStore = persistence.NewStore("bbgo", "slack")
+	if err := sessionStore.Load(&sessions); err != nil {
+		log.WithError(err).Errorf("sessions load error")
+	} else {
+		for _, session := range sessions {
+			if session.IsAuthorized() {
+				// notifier.AddChat(session.Chat)
+			}
 		}
 
-		log.Debugf("adding slack notifier with default channel: %s", conf.DefaultChannel)
-
-		var notifier = slacknotifier.New(slackToken, conf.DefaultChannel)
-		environ.AddNotifier(notifier)
+		// you must restore the session after the notifier updates
+		// messenger.RestoreSessions(sessions)
 	}
+
+	messenger.OnAuthorized(func(userSession *interact.SlackSession) {
+		if userSession.IsAuthorized() {
+			// notifier.AddChat(userSession.Chat)
+		}
+
+	})
+	interact.AddMessenger(messenger)
 }
 
 func (environ *Environment) setupTelegram(userConfig *Config, telegramBotToken string, persistence service.PersistenceService) error {
@@ -712,10 +761,7 @@ func (environ *Environment) setupTelegram(userConfig *Config, telegramBotToken s
 	environ.Notifiability.AddNotifier(notifier)
 
 	// allocate a store, so that we can save the chatID for the owner
-	var messenger = &interact.Telegram{
-		Bot:     bot,
-		Private: true,
-	}
+	var messenger = interact.NewTelegram(bot)
 
 	var sessions = interact.TelegramSessionMap{}
 	var sessionStore = persistence.NewStore("bbgo", "telegram", telegramID)
@@ -745,7 +791,7 @@ func (environ *Environment) setupTelegram(userConfig *Config, telegramBotToken s
 		}
 	})
 
-	interact.SetMessenger(messenger)
+	interact.AddMessenger(messenger)
 	return nil
 }
 
diff --git a/pkg/interact/default.go b/pkg/interact/default.go
index 26e08757c..4174122e6 100644
--- a/pkg/interact/default.go
+++ b/pkg/interact/default.go
@@ -8,8 +8,8 @@ func Default() *Interact {
 	return defaultInteraction
 }
 
-func SetMessenger(messenger Messenger) {
-	defaultInteraction.SetMessenger(messenger)
+func AddMessenger(messenger Messenger) {
+	defaultInteraction.AddMessenger(messenger)
 }
 
 func AddCustomInteraction(custom CustomInteraction) {
diff --git a/pkg/interact/interact.go b/pkg/interact/interact.go
index 67f64740f..3b3b20d86 100644
--- a/pkg/interact/interact.go
+++ b/pkg/interact/interact.go
@@ -50,7 +50,7 @@ type Interact struct {
 
 	customInteractions []CustomInteraction
 
-	messenger Messenger
+	messengers []Messenger
 }
 
 func New() *Interact {
@@ -172,12 +172,12 @@ func (it *Interact) runCommand(session Session, command string, args []string, c
 	return nil
 }
 
-func (it *Interact) SetMessenger(messenger Messenger) {
+func (it *Interact) AddMessenger(messenger Messenger) {
 	// pass Responder function
 	messenger.SetTextMessageResponder(func(session Session, message string, reply Reply, ctxObjects ...interface{}) error {
 		return it.handleResponse(session, message, append(ctxObjects, reply)...)
 	})
-	it.messenger = messenger
+	it.messengers = append(it.messengers, messenger)
 }
 
 // builtin initializes the built-in commands
@@ -222,21 +222,24 @@ func (it *Interact) registerCommands(commands map[string]*Command) error {
 		}
 
 		// register commands to the service
-		if it.messenger == nil {
+		if len(it.messengers) == 0 {
 			return fmt.Errorf("messenger is not set")
 		}
 
+		// commandName is used in the closure, we need to copy the variable
 		commandName := n
-		it.messenger.AddCommand(cmd, func(session Session, message string, reply Reply, ctxObjects ...interface{}) error {
-			args := parseCommand(message)
-			return it.runCommand(session, commandName, args, append(ctxObjects, reply)...)
-		})
+		for _, messenger := range it.messengers {
+			messenger.AddCommand(cmd, func(session Session, message string, reply Reply, ctxObjects ...interface{}) error {
+				args := parseCommand(message)
+				return it.runCommand(session, commandName, args, append(ctxObjects, reply)...)
+			})
+		}
 	}
 	return nil
 }
 
 func (it *Interact) Start(ctx context.Context) error {
-	if it.messenger == nil {
+	if len(it.messengers) == 0 {
 		log.Warn("messenger is not set, skip initializing")
 		return nil
 	}
@@ -256,6 +259,8 @@ func (it *Interact) Start(ctx context.Context) error {
 	}
 
 	// TODO: use go routine and context
-	it.messenger.Start(ctx)
+	for _, m := range it.messengers {
+		m.Start(ctx)
+	}
 	return nil
 }
diff --git a/pkg/interact/interact_test.go b/pkg/interact/interact_test.go
index ca891f3c2..bd0828240 100644
--- a/pkg/interact/interact_test.go
+++ b/pkg/interact/interact_test.go
@@ -105,7 +105,7 @@ func TestCustomInteraction(t *testing.T) {
 	telegram := &Telegram{
 		Bot: b,
 	}
-	globalInteraction.SetMessenger(telegram)
+	globalInteraction.AddMessenger(telegram)
 
 	testInteraction := &TestInteraction{}
 	testInteraction.Commands(globalInteraction)
diff --git a/pkg/interact/slack.go b/pkg/interact/slack.go
new file mode 100644
index 000000000..863d921b7
--- /dev/null
+++ b/pkg/interact/slack.go
@@ -0,0 +1,164 @@
+package interact
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/sirupsen/logrus"
+	"github.com/slack-go/slack"
+	"github.com/slack-go/slack/slackevents"
+	"github.com/slack-go/slack/socketmode"
+)
+
+type SlackSession struct {
+	BaseSession
+}
+
+type SlackSessionMap map[int64]*SlackSession
+
+//go:generate callbackgen -type Slack
+type Slack struct {
+	client *slack.Client
+	socket *socketmode.Client
+
+	sessions SlackSessionMap
+
+	commands []*Command
+
+	// textMessageResponder is used for interact to register its message handler
+	textMessageResponder Responder
+
+	authorizedCallbacks []func(userSession *SlackSession)
+}
+
+func NewSlack(client *slack.Client) *Slack {
+	socket := socketmode.New(
+		client,
+		socketmode.OptionDebug(true),
+		socketmode.OptionLog(
+			log.New(os.Stdout, "socketmode: ",
+				log.Lshortfile|log.LstdFlags)),
+	)
+
+	return &Slack{
+		client: client,
+		socket: socket,
+	}
+}
+
+func (s *Slack) SetTextMessageResponder(responder Responder) {
+	s.textMessageResponder = responder
+}
+
+func (s *Slack) AddCommand(command *Command, responder Responder) {
+	s.commands = append(s.commands, command)
+}
+
+func (s *Slack) listen() {
+	for evt := range s.socket.Events {
+		switch evt.Type {
+		case socketmode.EventTypeConnecting:
+			fmt.Println("Connecting to Slack with Socket Mode...")
+		case socketmode.EventTypeConnectionError:
+			fmt.Println("Connection failed. Retrying later...")
+		case socketmode.EventTypeConnected:
+			fmt.Println("Connected to Slack with Socket Mode.")
+		case socketmode.EventTypeEventsAPI:
+			eventsAPIEvent, ok := evt.Data.(slackevents.EventsAPIEvent)
+			if !ok {
+				fmt.Printf("Ignored %+v\n", evt)
+
+				continue
+			}
+
+			fmt.Printf("Event received: %+v\n", eventsAPIEvent)
+
+			s.socket.Ack(*evt.Request)
+
+			switch eventsAPIEvent.Type {
+			case slackevents.CallbackEvent:
+				innerEvent := eventsAPIEvent.InnerEvent
+				switch ev := innerEvent.Data.(type) {
+				case *slackevents.AppMentionEvent:
+					_, _, err := s.client.PostMessage(ev.Channel, slack.MsgOptionText("Yes, hello.", false))
+					if err != nil {
+						fmt.Printf("failed posting message: %v", err)
+					}
+				case *slackevents.MemberJoinedChannelEvent:
+					fmt.Printf("user %q joined to channel %q", ev.User, ev.Channel)
+				}
+			default:
+				s.socket.Debugf("unsupported Events API event received")
+			}
+		case socketmode.EventTypeInteractive:
+			callback, ok := evt.Data.(slack.InteractionCallback)
+			if !ok {
+				fmt.Printf("Ignored %+v\n", evt)
+
+				continue
+			}
+
+			fmt.Printf("Interaction received: %+v\n", callback)
+
+			var payload interface{}
+
+			switch callback.Type {
+			case slack.InteractionTypeBlockActions:
+				// See https://api.slack.com/apis/connections/socket-implement#button
+
+				s.socket.Debugf("button clicked!")
+			case slack.InteractionTypeShortcut:
+			case slack.InteractionTypeViewSubmission:
+				// See https://api.slack.com/apis/connections/socket-implement#modal
+			case slack.InteractionTypeDialogSubmission:
+			default:
+
+			}
+
+			s.socket.Ack(*evt.Request, payload)
+		case socketmode.EventTypeSlashCommand:
+			cmd, ok := evt.Data.(slack.SlashCommand)
+			if !ok {
+				fmt.Printf("Ignored %+v\n", evt)
+
+				continue
+			}
+
+			s.socket.Debugf("Slash command received: %+v", cmd)
+
+			payload := map[string]interface{}{
+				"blocks": []slack.Block{
+					slack.NewSectionBlock(
+						&slack.TextBlockObject{
+							Type: slack.MarkdownType,
+							Text: "foo",
+						},
+						nil,
+						slack.NewAccessory(
+							slack.NewButtonBlockElement(
+								"",
+								"somevalue",
+								&slack.TextBlockObject{
+									Type: slack.PlainTextType,
+									Text: "bar",
+								},
+							),
+						),
+					),
+				}}
+
+			s.socket.Ack(*evt.Request, payload)
+		default:
+			fmt.Fprintf(os.Stderr, "Unexpected event type received: %s\n", evt.Type)
+		}
+	}
+}
+
+func (s *Slack) Start(ctx context.Context) {
+	go s.listen()
+	if err := s.socket.Run() ; err != nil {
+		logrus.WithError(err).Errorf("slack socketmode error")
+	}
+}
diff --git a/pkg/interact/telegram.go b/pkg/interact/telegram.go
index 4d14ead7a..399b86de5 100644
--- a/pkg/interact/telegram.go
+++ b/pkg/interact/telegram.go
@@ -96,7 +96,7 @@ type Telegram struct {
 
 	authorizing bool
 
-	sessions map[int64]*TelegramSession
+	sessions TelegramSessionMap
 
 	// textMessageResponder is used for interact to register its message handler
 	textMessageResponder Responder
@@ -106,6 +106,14 @@ type Telegram struct {
 	authorizedCallbacks []func(s *TelegramSession)
 }
 
+func NewTelegram(bot *telebot.Bot) *Telegram {
+	return &Telegram{
+		Bot:      bot,
+		Private:  true,
+		sessions: make(map[int64]*TelegramSession),
+	}
+}
+
 func (tm *Telegram) SetTextMessageResponder(textMessageResponder Responder) {
 	tm.textMessageResponder = textMessageResponder
 }
@@ -213,6 +221,10 @@ func (tm *Telegram) RestoreSessions(sessions TelegramSessionMap) {
 	log.Infof("[telegram] restoring telegram %d sessions", len(sessions))
 	tm.sessions = sessions
 	for _, session := range sessions {
+		if session.Chat == nil || session.User == nil {
+			continue
+		}
+
 		if session.IsAuthorized() {
 			if _, err := tm.Bot.Send(session.Chat, fmt.Sprintf("Hi %s, I'm back. Your telegram session is restored.", session.User.Username)); err != nil {
 				log.WithError(err).Error("[telegram] can not send telegram message")
diff --git a/pkg/notifier/slacknotifier/slack.go b/pkg/notifier/slacknotifier/slack.go
index ec2199c2b..385897d2d 100644
--- a/pkg/notifier/slacknotifier/slack.go
+++ b/pkg/notifier/slacknotifier/slack.go
@@ -33,10 +33,8 @@ type Notifier struct {
 
 type NotifyOption func(notifier *Notifier)
 
-func New(token, channel string, options ...NotifyOption) *Notifier {
+func New(client *slack.Client, channel string, options ...NotifyOption) *Notifier {
 	// var client = slack.New(token, slack.OptionDebug(true))
-	var client = slack.New(token)
-
 	notifier := &Notifier{
 		channel: channel,
 		client:  client,