diff --git a/internal/api/oauth/callback.go b/internal/api/oauth/callback.go
index 4a9db74..d9e2513 100644
--- a/internal/api/oauth/callback.go
+++ b/internal/api/oauth/callback.go
@@ -68,7 +68,6 @@ func (h *handler) CallbackHandler() gin.HandlerFunc {
 
 		// Extract custom claims
 		// TODO: extract role from claims
-		// TODO: currently username = email, add Email in User model
 		var claims struct {
 			Email         string `json:"email"`
 			EmailVerified bool   `json:"email_verified"`
@@ -85,7 +84,7 @@ func (h *handler) CallbackHandler() gin.HandlerFunc {
 		}
 
 		// Check user existence
-		u, status := h.user.ProfileOrCreate(&user.CreateData{UserName: claims.Email, NickName: claims.Nickname})
+		u, status := h.user.ProfileOrCreate(&user.CreateData{Email: claims.Email, NickName: claims.Nickname})
 		if status != e.Success {
 			e.Pong[any](c, status, nil)
 			return
diff --git a/internal/api/user/create.go b/internal/api/user/create.go
index 1d1843a..d915463 100644
--- a/internal/api/user/create.go
+++ b/internal/api/user/create.go
@@ -8,7 +8,7 @@ import (
 )
 
 type createRequest struct {
-	UserName string `form:"username" json:"username" binding:"required"`
+	Email    string `form:"email"    json:"email"    binding:"required"`
 	NickName string `form:"nickname" json:"nickname" binding:"required"`
 	Password string `form:"password" json:"password" binding:"required"`
 }
@@ -19,7 +19,7 @@ type createRequest struct {
 // @Tags 	    user
 // @Accept      application/x-www-form-urlencoded
 // @Produce     json
-// @Param       username formData string true "username"
+// @Param       email    formData string true "email"
 // @Param       nickname formData string true "nickname"
 // @Param       password formData string true "password"
 // @Response    200 {object} e.Response[string] "jwt token"
@@ -33,7 +33,7 @@ func (h *handler) Create(c *gin.Context) {
 
 	// create user
 	createData := &user.CreateData{
-		UserName: req.UserName,
+		Email:    req.Email,
 		NickName: req.NickName,
 		Password: req.Password,
 	}
diff --git a/internal/api/user/login.go b/internal/api/user/login.go
index e9b515e..2fa8276 100644
--- a/internal/api/user/login.go
+++ b/internal/api/user/login.go
@@ -8,7 +8,7 @@ import (
 )
 
 type loginRequest struct {
-	UserName string `form:"username" json:"username" binding:"required"`
+	Email    string `form:"email"    json:"email"    binding:"required"`
 	Password string `form:"password" json:"password" binding:"required"`
 }
 
@@ -23,7 +23,7 @@ type LoginResponse struct {
 // @Tags 	    user
 // @Accept      application/x-www-form-urlencoded
 // @Produce     json
-// @Param       username formData string true "username"
+// @Param       email    formData string true "email"
 // @Param       password formData string true "password"
 // @Response    200 {object} e.Response[LoginResponse] "jwt token and user's nickname"
 // @Router      /v1/user/login [post]
@@ -36,7 +36,7 @@ func (h *handler) Login(c *gin.Context) {
 
 	// check password
 	loginData := &user.LoginData{
-		UserName: req.UserName,
+		Email:    req.Email,
 		Password: req.Password,
 	}
 	u, status := h.userService.Login(loginData)
diff --git a/internal/model/User.go b/internal/model/User.go
index 532d149..eebefd8 100644
--- a/internal/model/User.go
+++ b/internal/model/User.go
@@ -6,8 +6,8 @@ import (
 
 type User struct {
 	gorm.Model `json:"meta"`
-	UserName   string `json:"user_name"  gorm:"not null;uniqueIndex"`
-	NickName   string `json:"nick_name"  gorm:"not null"`
+	Email      string `json:"email"      gorm:"not null;uniqueIndex"`
+	NickName   string `json:"nick_name"  gorm:"not null;uniqueIndex"`
 	Role       Role   `json:"role"       gorm:"not null"`
 	Password   []byte `json:"-"`
 	IsEnabled  bool   `json:"is_enabled" gorm:"not null;index"`
diff --git a/internal/service/user/create.go b/internal/service/user/create.go
index c537fb2..a847bca 100644
--- a/internal/service/user/create.go
+++ b/internal/service/user/create.go
@@ -9,7 +9,7 @@ import (
 )
 
 type CreateData struct {
-	UserName string
+	Email    string
 	NickName string
 	Password string
 }
@@ -22,7 +22,7 @@ func (s *service) Create(data *CreateData) (*model.User, e.Status) {
 	}
 
 	user := &model.User{
-		UserName:  data.UserName,
+		Email:     data.Email,
 		NickName:  data.NickName,
 		Password:  hashed,
 		Role:      model.RoleGeneral,
diff --git a/internal/service/user/login.go b/internal/service/user/login.go
index 7f99841..24ec8aa 100644
--- a/internal/service/user/login.go
+++ b/internal/service/user/login.go
@@ -10,12 +10,12 @@ import (
 )
 
 type LoginData struct {
-	UserName string
+	Email    string
 	Password string
 }
 
 func (s *service) Login(data *LoginData) (*model.User, e.Status) {
-	user := &model.User{UserName: data.UserName}
+	user := &model.User{Email: data.Email}
 
 	err := s.db.Get().Where(user).First(&user).Error
 	if errors.Is(err, gorm.ErrRecordNotFound) {
diff --git a/internal/service/user/profile.go b/internal/service/user/profile.go
index 4c84e64..1ea5154 100644
--- a/internal/service/user/profile.go
+++ b/internal/service/user/profile.go
@@ -25,7 +25,7 @@ func (s *service) Profile(uid uint) (*model.User, e.Status) {
 
 func (s *service) ProfileOrCreate(data *CreateData) (*model.User, e.Status) {
 	user := &model.User{
-		UserName:  data.UserName,
+		Email:     data.Email,
 		NickName:  data.NickName,
 		Role:      model.RoleGeneral,
 		IsEnabled: true,
@@ -33,7 +33,7 @@ func (s *service) ProfileOrCreate(data *CreateData) (*model.User, e.Status) {
 
 	// Notice: FirstOrCreate will not update the record if it exists, and also we should not update the record
 	// Notice: OAuth2 created user will not have password
-	err := s.db.Get().Where(model.User{UserName: data.UserName}).FirstOrCreate(&user, data).Error
+	err := s.db.Get().Where(model.User{Email: data.Email}).FirstOrCreate(&user, data).Error
 	if err != nil {
 		s.log.Warn("DatabaseError", zap.Error(err), zap.Any("user", user))
 		return nil, e.DatabaseError