diff --git a/models/error.go b/models/error.go
index 6733b2a..794f9f7 100644
--- a/models/error.go
+++ b/models/error.go
@@ -2,6 +2,10 @@ package models
 
 import "fmt"
 
+// =====================
+// User Operation Errors
+// =====================
+
 // ErrUsernameExists represents a "UsernameAlreadyExists" kind of error.
 type ErrUsernameExists struct {
 	UserID   int64
@@ -17,3 +21,18 @@ func IsErrUsernameExists(err error) bool {
 func (err ErrUsernameExists) Error() string {
 	return fmt.Sprintf("a user with this username does already exist [user id: %d, username: %s]", err.UserID, err.Username)
 }
+
+// ErrNoUsername represents a "UsernameAlreadyExists" kind of error.
+type ErrNoUsername struct {
+	UserID int64
+}
+
+// IsErrNoUsername checks if an error is a ErrUsernameExists.
+func IsErrNoUsername(err error) bool {
+	_, ok := err.(ErrNoUsername)
+	return ok
+}
+
+func (err ErrNoUsername) Error() string {
+	return fmt.Sprintf("you need to specify a username [user id: %d]", err.UserID)
+}
diff --git a/models/user.go b/models/user.go
index 799284f..b282775 100644
--- a/models/user.go
+++ b/models/user.go
@@ -42,7 +42,7 @@ func (User) TableName() string {
 // GetUserByID gets informations about a user by its ID
 func GetUserByID(id int64) (user User, exists bool, err error) {
 	// Apparently xorm does otherwise look for all users but return only one, which leads to returing one even if the ID is 0
-	if user.ID == 0 {
+	if id == 0 {
 		return User{}, false, nil
 	}
 
diff --git a/models/user_add_update.go b/models/user_add_update.go
index ffb5251..6a898fb 100644
--- a/models/user_add_update.go
+++ b/models/user_add_update.go
@@ -52,7 +52,7 @@ func hashPassword(password string) (string, error) {
 func UpdateUser(user User) (updatedUser User, err error) {
 	// Check if we have at least a username
 	if user.Username == "" {
-		return User{}, fmt.Errorf("you need to specify at least a username and a password")
+		return User{}, ErrNoUsername{user.ID}
 	}
 
 	// Check if it exists
diff --git a/routes/api/v1/user_add_update.go b/routes/api/v1/user_add_update.go
index 5723c4a..f63993d 100644
--- a/routes/api/v1/user_add_update.go
+++ b/routes/api/v1/user_add_update.go
@@ -57,9 +57,16 @@ func UserAddOrUpdate(c echo.Context) error {
 	}
 
 	if err != nil {
+		// Check for user already exists
 		if models.IsErrUsernameExists(err) {
-			return c.JSON(http.StatusBadRequest, models.Message{"A user with this username already exists"})
+			return c.JSON(http.StatusBadRequest, models.Message{"A user with this username already exists."})
 		}
+
+		// Check for no username provided
+		if models.IsErrNoUsername(err) {
+			return c.JSON(http.StatusBadRequest, models.Message{"Please specify a username."})
+		}
+
 		return c.JSON(http.StatusInternalServerError, models.Message{"Error"})
 	}
 
diff --git a/routes/routes.go b/routes/routes.go
index f449328..f772c42 100644
--- a/routes/routes.go
+++ b/routes/routes.go
@@ -110,6 +110,7 @@ func RegisterRoutes(e *echo.Echo) {
 
 	a.GET("/users", apiv1.UsersList)
 	a.PUT("/users", apiv1.UserAddOrUpdate)
+	a.POST("/users/:id", apiv1.UserAddOrUpdate)
 
 	// Manage Users