diff --git a/catalog/dto/product.go b/catalog/dto/product.go
index 70ce275..5d35ea1 100644
--- a/catalog/dto/product.go
+++ b/catalog/dto/product.go
@@ -14,7 +14,7 @@ type GetProductResponseDTO struct {
 	Slug      string     `json:"slug"`
 	Price     float64    `json:"price"`
 	CreatedAt time.Time  `json:"created_at"`
-	UpdatedAt *time.Time `json:"updated_at,omitempty"`
+	UpdatedAt *time.Time `json:"updated_at"`
 }
 
 type GetProductListRequestDTO struct {
diff --git a/identity/entity/user.go b/identity/entity/user.go
index 5a4ba4b..8a69b23 100644
--- a/identity/entity/user.go
+++ b/identity/entity/user.go
@@ -3,12 +3,12 @@ package identity
 import "time"
 
 type User struct {
-	ID         string    `db:"id" json:"id"`
-	Email      string    `db:"email" json:"email"`
-	Username   string    `db:"username" json:"username"`
-	Password   string    `db:"password" json:"password"`
-	CreatedAt  time.Time `db:"created_at" json:"created_at"`
-	ModifiedAt time.Time `db:"modified_at" json:"modified_at"` // FIXME: zero-value issue
+	ID        string     `db:"id" json:"id"`
+	Email     string     `db:"email" json:"email"`
+	Username  string     `db:"username" json:"username"`
+	Password  string     `db:"password" json:"password"`
+	CreatedAt time.Time  `db:"created_at" json:"created_at"`
+	UpdatedAt *time.Time `db:"updated_at,omitempty" json:"updated_at,omitempty"` // FIXME: zero-value issue
 }
 
 // var TestUser = &User{