diff --git a/backend/controllers/authController.js b/backend/controllers/authController.js
index e4a7c51..4fabb7a 100644
--- a/backend/controllers/authController.js
+++ b/backend/controllers/authController.js
@@ -3,9 +3,12 @@ import { register, activateUser, login, logout } from '../services/authService.j
 const registerUser = async (req, res, next) => {
   try {
     const { email, password } = req.body;
+    console.log('registerUser', email, password);
     await register(email, password);
+    console.log('registerUser done');
     // Aus Sicherheitsgründen KEINE Userdaten (Passwort-Hash, Aktivierungscode, ...) zurückgeben
     res.status(201).json({ success: true });
+    console.log('registerUser response sent');
   } catch (error) {
     next(error);
   }
diff --git a/frontend/src/apiClient.js b/frontend/src/apiClient.js
index c29713e..830724b 100644
--- a/frontend/src/apiClient.js
+++ b/frontend/src/apiClient.js
@@ -1,7 +1,8 @@
 import axios from 'axios';
 import store from './store';
 
-export const backendBaseUrl = import.meta.env.VITE_BACKEND || 'http://localhost:3005';
+export const backendBaseUrl = import.meta.env.VITE_BACKEND
+  || (import.meta.env.DEV ? 'http://localhost:3005' : window.location.origin);
 
 const apiClient = axios.create({
   baseURL: `${backendBaseUrl}/api`,
diff --git a/frontend/src/views/Activate.vue b/frontend/src/views/Activate.vue
index 31bf58d..45cba40 100644
--- a/frontend/src/views/Activate.vue
+++ b/frontend/src/views/Activate.vue
@@ -27,7 +27,7 @@
 </template>
   
   <script>
-  import axios from 'axios';
+  import apiClient from '../apiClient.js';
   
   import InfoDialog from '../components/InfoDialog.vue';
 import ConfirmDialog from '../components/ConfirmDialog.vue';
@@ -63,7 +63,7 @@ export default {
       async activate() {
         try {
           const activationCode = this.$route.params.activationCode;
-          await axios.get(`/api/auth/activate/${activationCode}`);
+          await apiClient.get(`/auth/activate/${activationCode}`);
           await this.showInfo(this.$t('messages.success'), this.$t('auth.accountActivated'), '', 'success');
           this.$router.push('/login');
         } catch (error) {
diff --git a/frontend/src/views/Login.vue b/frontend/src/views/Login.vue
index 77a110b..8e7c646 100644
--- a/frontend/src/views/Login.vue
+++ b/frontend/src/views/Login.vue
@@ -34,8 +34,8 @@
 </template>
 
 <script>
-import axios from 'axios';
 import { mapActions } from 'vuex';
+import apiClient from '../apiClient.js';
 import InfoDialog from '../components/InfoDialog.vue';
 import ConfirmDialog from '../components/ConfirmDialog.vue';
 import { buildInfoConfig, buildConfirmConfig, safeErrorMessage } from '../utils/dialogUtils.js';
@@ -92,8 +92,8 @@ export default {
     ...mapActions(['login']),
     async executeLogin() {
       try {
-        const response = await axios.post(`${import.meta.env.VITE_BACKEND || 'http://localhost:3005'}/api/auth/login`, { email: this.email, password: this.password }, {
-          timeout: 5000, 
+        const response = await apiClient.post('/auth/login', { email: this.email, password: this.password }, {
+          timeout: 5000,
         });
         await this.login({ token: response.data.token, username: this.email }); 
         this.$router.push('/'); 
diff --git a/frontend/src/views/Register.vue b/frontend/src/views/Register.vue
index b7f65b6..718ef95 100644
--- a/frontend/src/views/Register.vue
+++ b/frontend/src/views/Register.vue
@@ -35,7 +35,7 @@
 </template>
   
   <script>
-  import axios from 'axios';
+  import apiClient from '../apiClient.js';
   
   import InfoDialog from '../components/InfoDialog.vue';
 import ConfirmDialog from '../components/ConfirmDialog.vue';
@@ -92,7 +92,7 @@ export default {
         
       async register() {
         try {
-          await axios.post(`${import.meta.env.VITE_BACKEND || 'http://localhost:3005'}/api/auth/register`, { email: this.email, password: this.password });
+          await apiClient.post('/auth/register', { email: this.email, password: this.password });
           await this.showInfo(this.$t('messages.success'), this.$t('auth.registerSuccess'), '', 'success');
         } catch (error) {
           const message = safeErrorMessage(error, this.$t('auth.registerFailed'));