diff --git a/code/backend/src/controllers/userController.ts b/code/backend/src/controllers/userController.ts
index 5813f21..7c384f5 100644
--- a/code/backend/src/controllers/userController.ts
+++ b/code/backend/src/controllers/userController.ts
@@ -37,6 +37,7 @@ export const registerUser = async (req: Request, res: Response) => {
       error: "Invalid data",
       details: [{ message: `User "${username}" already exists` }],
     });
+    return;
   }
   const hashedPassword = await bcrypt.hash(password, 10); // hash the password with bcrypt
   if (!hashedPassword) {
@@ -45,6 +46,7 @@ export const registerUser = async (req: Request, res: Response) => {
       error: "Invalid data",
       details: [{ message: "Server Error" }],
     });
+    return;
   }
   const userData = {
     // create a new user object with the data from the request body and the hashed password
@@ -59,6 +61,7 @@ export const registerUser = async (req: Request, res: Response) => {
       error: "Server error",
       details: [{ message: "Server Error while creating user" }],
     });
+    return;
   }
   const token: string = generateAccessToken(user.username, user.id); // generate a JWT token with the username and userId as payload
   res.set("Authorization", `Bearer ${token}`); // set the token in the response header
@@ -77,6 +80,7 @@ export const loginUser = async (req: Request, res: Response) => {
       error: "Invalid data",
       details: [{ message: "Username and password are required" }],
     });
+    return;
   }
   const user = await prisma.user.findUnique({
     // check if the user exists
@@ -86,7 +90,12 @@ export const loginUser = async (req: Request, res: Response) => {
   });
   if (!user) {
     // if the user does not exist, return an error message
-    res.status(400).json({ message: `User "${username}" not found` });
+    res
+      .status(400)
+      .json({
+        error: "user not found",
+        details: [{ message: `User "${username}" not found` }],
+      });
     return;
   }
   const isPasswordValid = await bcrypt.compare(password, user.password); // compare the password with the hashed password in the database
@@ -96,6 +105,7 @@ export const loginUser = async (req: Request, res: Response) => {
       error: "invalid credentials",
       details: [{ message: "Invalid password" }],
     });
+    return;
   }
   const token: string = generateAccessToken(user.username, user.id); // generate a JWT token with the username and userId as payload
   res.set("Authorization", `Bearer ${token}`); // set the token in the response header
@@ -110,6 +120,7 @@ export const getUser = async (req: Request, res: Response) => {
       error: "no username",
       details: [{ message: "Username is required" }],
     });
+    return;
   }
   const user = await prisma.user.findUnique({
     where: {
diff --git a/code/backend/src/middleware/authenticateToken.ts b/code/backend/src/middleware/authenticateToken.ts
index a0d6eee..ba5c856 100644
--- a/code/backend/src/middleware/authenticateToken.ts
+++ b/code/backend/src/middleware/authenticateToken.ts
@@ -32,24 +32,25 @@ export function authenticateToken() {
     else {
       jwt.verify(token, JWT_SECRET, (err: any, user: any) => {
         // verify the token with the secret
-        console.log(err);
+
         if (err) {
-          if (err instanceof TokenExpiredError)
+          if (err instanceof TokenExpiredError) {
             // check if the error is expired and return 401
-            res
-              .status(401)
-              .json({
-                error: "Token expired",
-                details: [{ message: "Token expired" }],
-              });
+            res.status(401).json({
+              error: "Token expired",
+              details: [{ message: "Token expired" }],
+            });
+            return;
+          }
+
           // if the token is invalid, return 403 Forbidden
-          else
-            res
-              .status(403)
-              .json({
-                error: "Invalid token",
-                details: [{ message: "Invalid token" }],
-              });
+          else {
+            res.status(403).json({
+              error: "Invalid token",
+              details: [{ message: "Invalid token" }],
+            });
+            return;
+          }
         }
         next();
       });
diff --git a/code/backend/src/middleware/validationMiddleware.ts b/code/backend/src/middleware/validationMiddleware.ts
index f1447e8..ed307e8 100644
--- a/code/backend/src/middleware/validationMiddleware.ts
+++ b/code/backend/src/middleware/validationMiddleware.ts
@@ -16,10 +16,12 @@ export function validateData(schema: z.ZodObject<any, any>) {
         res
           .status(StatusCodes.BAD_REQUEST)
           .json({ error: "Invalid data", details: errorMessages });
+        return;
       } else {
         res
           .status(StatusCodes.INTERNAL_SERVER_ERROR)
           .json({ error: "Internal Server Error" });
+        return;
       }
     }
   };