diff --git a/TODO.org b/TODO.org
index 2d9882a..b007ee5 100644
--- a/TODO.org
+++ b/TODO.org
@@ -9,9 +9,9 @@ IPÊ
     - [ ] Escrever testes automatizados
     - [ ] SSL
 	- [ ] Expvar - Canais, inscritos
-    - [ ] Otimizações [0/3]
+    - [-] Otimizações [1/3]
       - [ ] Refatorar partes do código, remover repetições
-      - [ ] Alterar tipos de dados de slices para mapas em alguns locais.
+      - [X] Alterar tipos de dados de slices para mapas em alguns locais.
       - [ ] Remover Canais vazios com uma go routine - Uma especie de coletor de lixo
     - [ ] Segurança, tempo de expiração, etc
     - [X] Dados extra na conexão do usuário. Ver Websockets onOpen
diff --git a/app.go b/app.go
index 6f2b4d9..bf9f008 100644
--- a/app.go
+++ b/app.go
@@ -25,24 +25,56 @@ type App struct {
 	WebHooks            bool
 	URLWebHook          string
 
-	PublicChannels   []*Channel `json:"-"`
-	PresenceChannels []*Channel `json:"-"`
-	PrivateChannels  []*Channel `json:"-"`
-
+	Channels    map[string]*Channel    `json:"-"`
 	Subscribers map[string]*Subscriber `json:"-"`
 }
 
-// Returns a list of all channels in this app
-func (a *App) AllChannels() []*Channel {
+// Alloc memory for Subscribers and Channels
+func (a *App) Init() {
+	a.Subscribers = make(map[string]*Subscriber)
+	a.Channels = make(map[string]*Channel)
+}
+
+// Only Presence channels
+func (a *App) PresenceChannels() []*Channel {
 	var channels []*Channel
 
-	channels = append(channels, a.PrivateChannels...)
-	channels = append(channels, a.PresenceChannels...)
-	channels = append(channels, a.PublicChannels...)
+	for _, c := range a.Channels {
+		if c.IsPresence() {
+			channels = append(channels, c)
+		}
+	}
 
 	return channels
 }
 
+// Only Private channels
+func (a *App) PrivateChannels() []*Channel {
+	var channels []*Channel
+
+	for _, c := range a.Channels {
+		if c.IsPrivate() {
+			channels = append(channels, c)
+		}
+	}
+
+	return channels
+}
+
+// Only Public channels
+func (a *App) PublicChannels() []*Channel {
+	var channels []*Channel
+
+	for _, c := range a.Channels {
+		if c.IsPublic() {
+			channels = append(channels, c)
+		}
+	}
+
+	return channels
+}
+
+// Disconnect Socket
 func (a *App) Disconnect(socketID string) {
 	log.Infof("Disconnecting socket %+v", socketID)
 
@@ -54,7 +86,7 @@ func (a *App) Disconnect(socketID string) {
 	}
 
 	// Unsubscribe from channels
-	for _, c := range a.AllChannels() {
+	for _, c := range a.Channels {
 		if c.IsSubscribed(s) {
 			c.Unsubscribe(a, s)
 		}
@@ -72,7 +104,7 @@ func (a *App) Disconnect(socketID string) {
 	a.Unlock()
 }
 
-// Create a new Subscriber
+// Connect a new Subscriber
 func (a *App) Connect(s *Subscriber) {
 	log.Infof("Adding a new Subscriber %s to app %s", s.SocketID, a.Name)
 	a.Lock()
@@ -97,15 +129,7 @@ func (a *App) AddChannel(c *Channel) {
 	log.Infof("Adding a new channel %s to app %s", c.ChannelID, a.Name)
 
 	a.Lock()
-
-	if c.IsPresence() {
-		a.PresenceChannels = append(a.PresenceChannels, c)
-	} else if c.IsPrivate() {
-		a.PrivateChannels = append(a.PrivateChannels, c)
-	} else {
-		a.PublicChannels = append(a.PublicChannels, c)
-	}
-
+	a.Channels[c.ChannelID] = c
 	a.Unlock()
 }
 
@@ -125,10 +149,10 @@ func (a *App) FindOrCreateChannelByChannelID(n string) *Channel {
 // Find the channel by channel ID
 func (a *App) FindChannelByChannelID(n string) (*Channel, error) {
 
-	for _, c := range a.AllChannels() {
-		if c.ChannelID == n {
-			return c, nil
-		}
+	c, exists := a.Channels[n]
+
+	if exists {
+		return c, nil
 	}
 
 	return nil, errors.New("Channel does not exists")
diff --git a/config.go b/config.go
index cb26f41..6388c6d 100644
--- a/config.go
+++ b/config.go
@@ -15,9 +15,10 @@ type ConfigFile struct {
 // Error for App not found
 var AppNotFoundError = errors.New("App not found")
 
-func (c *ConfigFile) Initialize() {
+// Initialize Apps
+func (c *ConfigFile) Init() {
 	for _, app := range c.Apps {
-		app.Subscribers = make(map[string]*Subscriber)
+		app.Init()
 	}
 }
 
diff --git a/conn.go b/conn.go
index 8001db6..50e017b 100644
--- a/conn.go
+++ b/conn.go
@@ -9,7 +9,6 @@ import (
 	"errors"
 	"strings"
 	"sync"
-
 	"time"
 
 	log "github.com/golang/glog"
@@ -47,7 +46,7 @@ type Channel struct {
 
 	CreatedAt     time.Time
 	ChannelID     string
-	Subscriptions []*Subscription
+	Subscriptions map[string]*Subscription
 }
 
 // Return true if the channel has at least one subscriber
@@ -60,6 +59,11 @@ func (c *Channel) IsPresenceOrPrivate() bool {
 	return c.IsPresence() || c.IsPrivate()
 }
 
+// Check if the type of the channel is public
+func (c *Channel) IsPublic() bool {
+	return !c.IsPresence() && !c.IsPrivate()
+}
+
 // Check if the type of the channel is presence
 func (c *Channel) IsPresence() bool {
 	return strings.HasPrefix(c.ChannelID, "presence-")
@@ -86,7 +90,7 @@ func (c *Channel) Subscribe(a *App, s *Subscriber, data string) {
 	log.Infof("Subscribing %s to channel %s", s.SocketID, c.ChannelID)
 
 	c.Lock()
-	c.Subscriptions = append(c.Subscriptions, NewSubscription(s, data))
+	c.Subscriptions[s.SocketID] = NewSubscription(s, data)
 	c.Unlock()
 
 	if c.IsPresence() {
@@ -116,12 +120,8 @@ func (c *Channel) Subscribe(a *App, s *Subscriber, data string) {
 
 // IsSubscribed check if the user is subscribed
 func (c *Channel) IsSubscribed(s *Subscriber) bool {
-	for _, subs := range c.Subscriptions {
-		if subs.Subscriber == s {
-			return true
-		}
-	}
-	return false
+	_, exists := c.Subscriptions[s.SocketID]
+	return exists
 }
 
 // Remove the subscriber from the channel
@@ -132,17 +132,13 @@ func (c *Channel) Unsubscribe(a *App, s *Subscriber) error {
 	c.Lock()
 	defer c.Unlock()
 
-	index := -1
-	for i, subs := range c.Subscriptions {
-		if subs.Subscriber == s {
-			index = i
-			break
-		}
-	}
-	if index == -1 {
+	_, exists := c.Subscriptions[s.SocketID]
+
+	if !exists {
 		return errors.New("Subscription not found")
 	}
-	c.Subscriptions = append(c.Subscriptions[:index], c.Subscriptions[index+1:]...)
+
+	delete(c.Subscriptions, s.SocketID)
 
 	if c.IsPresence() {
 		// Publish pusher_internal:member_removed
@@ -162,7 +158,7 @@ func (c *Channel) Unsubscribe(a *App, s *Subscriber) error {
 func NewChannel(channelID string) *Channel {
 	log.Infof("Creating a new channel: %s", channelID)
 
-	return &Channel{ChannelID: channelID, CreatedAt: time.Now()}
+	return &Channel{ChannelID: channelID, CreatedAt: time.Now(), Subscriptions: make(map[string]*Subscription)}
 }
 
 // This function generate a sequencial ID
diff --git a/main.go b/main.go
index 57a58b6..de0169c 100644
--- a/main.go
+++ b/main.go
@@ -33,7 +33,7 @@ func main() {
 		log.Fatal(err)
 	}
 
-	Conf.Initialize()
+	Conf.Init()
 
 	router := NewRouter()
 
diff --git a/rest.go b/rest.go
index 2238b55..a071a66 100644
--- a/rest.go
+++ b/rest.go
@@ -136,7 +136,7 @@ func GetChannels(w http.ResponseWriter, r *http.Request) {
 
 	switch filter {
 	case "presence-":
-		for _, c := range app.PresenceChannels {
+		for _, c := range app.PresenceChannels() {
 			if requestedUserCount {
 				channels[c.ChannelID] = struct {
 					UserCount int `json:"user_count"`
@@ -148,15 +148,15 @@ func GetChannels(w http.ResponseWriter, r *http.Request) {
 			}
 		}
 	case "public-":
-		for _, c := range app.PublicChannels {
+		for _, c := range app.PublicChannels() {
 			channels[c.ChannelID] = struct{}{}
 		}
 	case "private-":
-		for _, c := range app.PrivateChannels {
+		for _, c := range app.PrivateChannels() {
 			channels[c.ChannelID] = struct{}{}
 		}
 	default:
-		for _, c := range app.AllChannels() {
+		for _, c := range app.Channels {
 			channels[c.ChannelID] = struct{}{}
 		}
 	}