diff --git a/cmd/main/main.go b/cmd/main/main.go
index 5766644..586072a 100644
--- a/cmd/main/main.go
+++ b/cmd/main/main.go
@@ -12,6 +12,10 @@ import (
 	"github.com/urfave/cli/v2"
 )
 
+var (
+	cfg *config.Config
+)
+
 func main() {
 	app := setupApp()
 	if err := app.Run(os.Args); err != nil {
@@ -21,16 +25,40 @@ func main() {
 
 func setupApp() *cli.App {
 	app := &cli.App{
-		Name:  "serial-read",
-		Usage: "A serial port reading CLI application",
+		Name:  "telegram message process",
+		Usage: "A Civial Aviation Authority Telegram message processor",
 		Before: func(c *cli.Context) error {
-			// parameter = config.GetParameter()
+			cfg, err := config.LoadConfig()
+			if err != nil {
+				fmt.Printf("Error loading configuration: %v\n", err)
+				return err
+			}
+
+			if err := config.ValidateConfig(cfg); err != nil {
+				fmt.Printf("Invalid configuration: %v\n", err)
+				return err
+			}
+			overrideConfig(c)
 			return nil
 		},
 		Commands: []*cli.Command{
 			{
-				Name:   "listen",
-				Usage:  "Listen to nats messages",
+				Name:  "listen",
+				Usage: "Listen to nats messages",
+				Flags: []cli.Flag{
+					&cli.StringFlag{
+						Name:    "nats",
+						Usage:   "Nats server address",
+						Value:   "nats://localhost:4222",
+						EnvVars: []string{"NATS_SERVER"},
+					},
+					&cli.StringFlag{
+						Name:    "topic",
+						Usage:   "Nats topic to listen to",
+						Value:   "Telegram.Serial",
+						EnvVars: []string{"NATS_SUBJECT"},
+					},
+				},
 				Action: executeListen,
 			},
 		},
@@ -38,21 +66,19 @@ func setupApp() *cli.App {
 	return app
 }
 
+func overrideConfig(c *cli.Context) {
+	if c.IsSet("nats") {
+		cfg.Nats.URL = c.String("nats")
+	}
+	if c.IsSet("topic") {
+		cfg.Subscription.Topic = c.String("topic")
+	}
+}
+
 func executeListen(c *cli.Context) error {
-	cfg, err := config.LoadConfig()
+	// cfg, err := config.LoadConfig()
 	log := utils.GetLogger()
-	if err != nil {
-		fmt.Printf("Error loading configuration: %v\n", err)
-		return err
-	}
-
-	if err := config.ValidateConfig(cfg); err != nil {
-		fmt.Printf("Invalid configuration: %v\n", err)
-		return err
-	}
-
 	fmt.Println("Loaded configuration successfully")
-
 	log.Info("Starting nats subscriber")
 	handler := handlers.NewNatsHandler(cfg)
 
diff --git a/internal/handlers/nats_handler.go b/internal/handlers/message_handler.go
similarity index 80%
rename from internal/handlers/nats_handler.go
rename to internal/handlers/message_handler.go
index da002a1..f9c421f 100644
--- a/internal/handlers/nats_handler.go
+++ b/internal/handlers/message_handler.go
@@ -15,17 +15,17 @@ import (
 	nc "github.com/nats-io/nats.go"
 )
 
-type NatsHandler struct {
+type MessageHandler struct {
 	mu         sync.Mutex
 	config     *config.Config
 	hasuraRepo *repository.HasuraRepository
 }
 
-func NewNatsHandler(config *config.Config) *NatsHandler {
-	return &NatsHandler{config: config, hasuraRepo: repository.NewHasuraRepo(config.Hasura.Endpoint, config.Hasura.Secret)}
+func NewNatsHandler(config *config.Config) *MessageHandler {
+	return &MessageHandler{config: config, hasuraRepo: repository.NewHasuraRepo(config.Hasura.Endpoint, config.Hasura.Secret)}
 }
 
-func (n *NatsHandler) HandleMessage(msg *message.Message) error {
+func (n *MessageHandler) HandleMessage(msg *message.Message) error {
 	n.mu.Lock()
 	defer n.mu.Unlock()
 	log := utils.GetSugaredLogger()
@@ -45,7 +45,7 @@ func (n *NatsHandler) HandleMessage(msg *message.Message) error {
 	return nil
 }
 
-func (n *NatsHandler) SaveMessage(parsed *domain.ParsedMessage, uuid string) {
+func (n *MessageHandler) SaveMessage(parsed *domain.ParsedMessage, uuid string) {
 	logger := watermill.NewStdLogger(false, false)
 	if parsed != nil {
 		parsed.Uuid = uuid
diff --git a/internal/nats/sub.go b/internal/nats/sub.go
index 443abde..41cab76 100644
--- a/internal/nats/sub.go
+++ b/internal/nats/sub.go
@@ -10,7 +10,7 @@ import (
 	nc "github.com/nats-io/nats.go"
 )
 
-func Subscribe(config *config.Config, marshaler *handlers.PlainTextMarshaler, handler *handlers.NatsHandler) {
+func Subscribe(config *config.Config, marshaler *handlers.PlainTextMarshaler, handler *handlers.MessageHandler) {
 	// marshaler := &PlainTextMarshaler{}
 	logger := watermill.NewStdLogger(false, false)
 	options := []nc.Option{