diff --git a/internal/domain/auth/jwt.go b/internal/domain/auth/jwt.go
index aa3a3a4..58b21ca 100644
--- a/internal/domain/auth/jwt.go
+++ b/internal/domain/auth/jwt.go
@@ -40,7 +40,7 @@ func GenerateJwtToken(keyId int, userId int) (string, error) {
 	issuedAt := time.Now()
 	claims["iat"] = issuedAt.Unix()
 	claims["exp"] = issuedAt.Add(expiresIn).Unix()
-	claims["sub"] = strconv.Itoa(int(userId))
+	claims["sub"] = strconv.Itoa(userId)
 
 	tokenString, err := token.SignedString(secretKey)
 	if err != nil {
@@ -65,44 +65,43 @@ func GenerateTokenPair(userId int) (accessToken, refreshToken string, err error)
 	return
 }
 
-func ValidateToken(tokenString string) (isValid bool, userId int, keyId int, err error) {
-
-	var key []byte
+func ValidateJwtToken(tokenString string) (isValid bool, sub string, keyId int, err error) {
+	var secret []byte
 
 	claims := jwt.MapClaims{}
 
-	token, err := jwt.ParseWithClaims(
+	parsedToken, err := jwt.ParseWithClaims(
 		tokenString,
 		claims,
 		func(token *jwt.Token) (interface{}, error) {
-
 			keyId = int(token.Header["kid"].(float64))
 
 			switch keyId {
 			case AccessTokenKeyId:
-				key = []byte(config.Global.JwtAccessTokenSecret)
+				secret = []byte(config.Global.JwtAccessTokenSecret)
 			case RefreshTokenKeyId:
-				key = []byte(config.Global.JwtRefreshTokenSecret)
+				secret = []byte(config.Global.JwtRefreshTokenSecret)
 			}
 
-			return key, nil
+			return secret, nil
 		},
 	)
-
 	if err != nil {
 		common.Logger.Error("JWT validation failed: ", err)
 		return
 	}
 
-	if !token.Valid {
+	if !parsedToken.Valid {
 		err = errors.New("Invalid JWT token")
 		return
 	}
 
 	isValid = true
 
-	sub, err := claims.GetSubject()
-	userId, err = strconv.Atoi(sub)
+	sub, err = parsedToken.Claims.GetSubject()
+	if err != nil {
+		return
+	}
 
 	return
 }
diff --git a/internal/domain/auth/jwt_test.go b/internal/domain/auth/jwt_test.go
index fa8f046..eba9085 100644
--- a/internal/domain/auth/jwt_test.go
+++ b/internal/domain/auth/jwt_test.go
@@ -21,7 +21,7 @@ func TestGenerateAccessToken(t *testing.T) {
 		accessToken, err := GenerateJwtToken(AccessTokenKeyId, userId)
 		assert.NoError(t, err)
 
-		isValid, _, _, _ := ValidateToken(accessToken)
+		isValid, _, _, _ := ValidateJwtToken(accessToken)
 
 		if isValid != true {
 			t.Errorf(
diff --git a/internal/domain/auth/service.go b/internal/domain/auth/service.go
index 834e540..3690981 100644
--- a/internal/domain/auth/service.go
+++ b/internal/domain/auth/service.go
@@ -3,6 +3,7 @@ package auth
 import (
 	"errors"
 	"fmt"
+	"strconv"
 
 	"gin-starter/internal/domain/model"
 	"gin-starter/internal/domain/user"
@@ -86,9 +87,9 @@ func (s *AuthService) Logout(logoutDto *LogoutDto) error {
 	return s.AuthHelper.BlacklistToken(logoutDto.RefreshToken)
 }
 
-func (s *AuthService) RefreshToken(logoutDto *LogoutDto) (*LoginResponse, error) {
+func (s *AuthService) Refresh(logoutDto *LogoutDto) (*LoginResponse, error) {
 
-	isTokenValid, userId, keyId, err := ValidateToken(logoutDto.RefreshToken)
+	isTokenValid, userIdString, keyId, err := ValidateJwtToken(logoutDto.RefreshToken)
 	if err != nil {
 		return nil, err
 	}
@@ -115,6 +116,7 @@ func (s *AuthService) RefreshToken(logoutDto *LogoutDto) (*LoginResponse, error)
 		return nil, err
 	}
 
+	userId, err := strconv.Atoi(userIdString)
 	accessToken, refreshToken, err := GenerateTokenPair(userId)
 	if err != nil {
 		return nil, err
diff --git a/internal/infrastructure/controller/auth_controller.go b/internal/infrastructure/controller/auth_controller.go
index d799fd8..db634c8 100644
--- a/internal/infrastructure/controller/auth_controller.go
+++ b/internal/infrastructure/controller/auth_controller.go
@@ -107,14 +107,14 @@ func (a *authController) Logout(c *gin.Context) {
 // @Failure 400 {object} common.HttpError
 // @Failure 500 {object} common.HttpError
 // @Router /auth/refresh [post]
-func (a *authController) RefreshToken(c *gin.Context) {
+func (a *authController) Refresh(c *gin.Context) {
 	var refreshDto auth.LogoutDto
 	if err := c.BindJSON(&refreshDto); err != nil {
 		common.RaiseHttpError(c, http.StatusBadRequest, err)
 		return
 	}
 
-	refreshResponse, err := a.AuthService.RefreshToken(&refreshDto)
+	refreshResponse, err := a.AuthService.Refresh(&refreshDto)
 	if err != nil {
 		if errors.Is(err, auth.ErrTokenBlacklisted) {
 			common.RaiseHttpError(c, http.StatusUnauthorized, err)
diff --git a/internal/infrastructure/middleware/auth_middleware.go b/internal/infrastructure/middleware/auth_middleware.go
index 4a63ca4..22c1002 100644
--- a/internal/infrastructure/middleware/auth_middleware.go
+++ b/internal/infrastructure/middleware/auth_middleware.go
@@ -8,9 +8,9 @@ import (
 	"time"
 
 	"github.com/gin-gonic/gin"
-	"github.com/golang-jwt/jwt/v5"
 
 	"gin-starter/internal/config"
+	"gin-starter/internal/domain/auth"
 	"gin-starter/internal/domain/model"
 	"gin-starter/internal/infrastructure/controller"
 	"gin-starter/pkg/common"
@@ -36,34 +36,18 @@ func AuthMiddleware() gin.HandlerFunc {
 			return
 		}
 
-		claims := jwt.MapClaims{}
-		parsedToken, err := jwt.ParseWithClaims(
-			accessToken,
-			claims,
-			func(token *jwt.Token) (interface{}, error) {
-				return []byte(config.Global.JwtAccessTokenSecret), nil
-			},
-		)
-
+		isJwtValid, userIdString, _, err := auth.ValidateJwtToken(accessToken)
 		if err != nil {
-			if err == jwt.ErrSignatureInvalid {
-				raiseUnauthorizedError(c, "Invalid authorization token signature")
-				return
-			}
-			raiseUnauthorizedError(c, "Invalid authorization token")
-			return
-		}
-
-		if !parsedToken.Valid {
-			raiseUnauthorizedError(c, "Invalid authorization token")
+			common.RaiseHttpError(
+				c,
+				http.StatusUnauthorized,
+				err,
+			)
 			return
 		}
-
-		userIdString, err := parsedToken.Claims.GetSubject()
-		if err != nil {
-			raiseUnauthorizedError(c, "Missing subject in JWT")
+		if !isJwtValid {
+			raiseUnauthorizedError(c, "Invalid access token")
 			return
-
 		}
 
 		var user model.User
diff --git a/internal/infrastructure/server/router.go b/internal/infrastructure/server/router.go
index 3f95e57..1cbae4c 100644
--- a/internal/infrastructure/server/router.go
+++ b/internal/infrastructure/server/router.go
@@ -13,7 +13,7 @@ func registerAuthRoutes(g *gin.RouterGroup) {
 	g.POST("/register", controllers.Register)
 	g.POST("/login", controllers.Login)
 	g.POST("/logout", controllers.Logout, middleware.AuthMiddleware())
-	g.POST("/refresh", controllers.RefreshToken)
+	g.POST("/refresh", controllers.Refresh)
 }
 
 func registerUserRoutes(g *gin.RouterGroup) {