diff --git a/README.md b/README.md
index db67387..7bb876a 100644
--- a/README.md
+++ b/README.md
@@ -168,7 +168,7 @@ Users report that [ESP_Flasher](https://github.com/Jason2866/ESP_Flasher/release
 ## First configuration
 * After the initial flashing of the microcontroller, an Access Point called "OpenDTU-*" is opened. The default password is "openDTU42".
 * Use a web browser to open the address [http://192.168.4.1](http://192.168.4.1)
-* Navigate to Settings --> Network Settings and enter your WiFi credentials
+* Navigate to Settings --> Network Settings and enter your WiFi credentials. The username to access the config menu is "admin" and the password the same as for accessing the Access Point (default: "openDTU42").
 * OpenDTU then simultaneously connects to your WiFi AP with this credentials. Navigate to Info --> Network and look into section "Network Interface (Station)" for the IP address received via DHCP.
 * When OpenDTU is connected to a configured WiFI AP, the "OpenDTU-*" Access Point is closed after 3 minutes.
 * OpenDTU needs access to a working NTP server to get the current date & time. Both are sent to the inverter with each request. Default NTP server is pool.ntp.org. If your network has different requirements please change accordingly (Settings --> NTP Settings).
diff --git a/include/WebApi.h b/include/WebApi.h
index cf7805a..699b9cd 100644
--- a/include/WebApi.h
+++ b/include/WebApi.h
@@ -24,6 +24,8 @@ public:
     void init();
     void loop();
 
+    static bool checkCredentials(AsyncWebServerRequest* request);
+
 private:
     AsyncWebServer _server;
     AsyncEventSource _events;
diff --git a/include/WebApi_security.h b/include/WebApi_security.h
index d94a7ee..ea9dd75 100644
--- a/include/WebApi_security.h
+++ b/include/WebApi_security.h
@@ -12,5 +12,7 @@ private:
     void onPasswordGet(AsyncWebServerRequest* request);
     void onPasswordPost(AsyncWebServerRequest* request);
 
+    void onAuthenticateGet(AsyncWebServerRequest* request);
+
     AsyncWebServer* _server;
 };
\ No newline at end of file
diff --git a/include/defaults.h b/include/defaults.h
index 298a87f..9656901 100644
--- a/include/defaults.h
+++ b/include/defaults.h
@@ -9,6 +9,7 @@
 
 #define ACCESS_POINT_NAME "OpenDTU-"
 #define ACCESS_POINT_PASSWORD "openDTU42"
+#define AUTH_USERNAME "admin"
 
 #define ADMIN_TIMEOUT 180
 #define WIFI_RECONNECT_TIMEOUT 15
diff --git a/src/WebApi.cpp b/src/WebApi.cpp
index be8203d..f6a6355 100644
--- a/src/WebApi.cpp
+++ b/src/WebApi.cpp
@@ -5,6 +5,7 @@
 #include "WebApi.h"
 #include "ArduinoJson.h"
 #include "AsyncJson.h"
+#include "Configuration.h"
 #include "defaults.h"
 
 WebApiClass::WebApiClass()
@@ -55,4 +56,22 @@ void WebApiClass::loop()
     _webApiWsLive.loop();
 }
 
+bool WebApiClass::checkCredentials(AsyncWebServerRequest* request)
+{
+    CONFIG_T& config = Configuration.get();
+    if (request->authenticate(AUTH_USERNAME, config.Security_Password)) {
+        return true;
+    }
+
+    AsyncWebServerResponse* r = request->beginResponse(401);
+
+    // WebAPI should set the X-Requested-With to prevent browser internal auth dialogs
+    if (!request->hasHeader("X-Requested-With")) {
+        r->addHeader(F("WWW-Authenticate"), F("Basic realm=\"Login Required\""));
+    }
+    request->send(r);
+
+    return false;
+}
+
 WebApiClass WebApi;
\ No newline at end of file
diff --git a/src/WebApi_security.cpp b/src/WebApi_security.cpp
index 2009be9..96802fb 100644
--- a/src/WebApi_security.cpp
+++ b/src/WebApi_security.cpp
@@ -6,6 +6,7 @@
 #include "ArduinoJson.h"
 #include "AsyncJson.h"
 #include "Configuration.h"
+#include "WebApi.h"
 #include "helper.h"
 
 void WebApiSecurityClass::init(AsyncWebServer* server)
@@ -16,6 +17,7 @@ void WebApiSecurityClass::init(AsyncWebServer* server)
 
     _server->on("/api/security/password", HTTP_GET, std::bind(&WebApiSecurityClass::onPasswordGet, this, _1));
     _server->on("/api/security/password", HTTP_POST, std::bind(&WebApiSecurityClass::onPasswordPost, this, _1));
+    _server->on("/api/security/authenticate", HTTP_GET, std::bind(&WebApiSecurityClass::onAuthenticateGet, this, _1));
 }
 
 void WebApiSecurityClass::loop()
@@ -24,6 +26,10 @@ void WebApiSecurityClass::loop()
 
 void WebApiSecurityClass::onPasswordGet(AsyncWebServerRequest* request)
 {
+    if (!WebApi.checkCredentials(request)) {
+        return;
+    }
+
     AsyncJsonResponse* response = new AsyncJsonResponse();
     JsonObject root = response->getRoot();
     const CONFIG_T& config = Configuration.get();
@@ -36,6 +42,10 @@ void WebApiSecurityClass::onPasswordGet(AsyncWebServerRequest* request)
 
 void WebApiSecurityClass::onPasswordPost(AsyncWebServerRequest* request)
 {
+    if (!WebApi.checkCredentials(request)) {
+        return;
+    }
+
     AsyncJsonResponse* response = new AsyncJsonResponse();
     JsonObject retMsg = response->getRoot();
     retMsg[F("type")] = F("warning");
@@ -87,6 +97,21 @@ void WebApiSecurityClass::onPasswordPost(AsyncWebServerRequest* request)
     retMsg[F("type")] = F("success");
     retMsg[F("message")] = F("Settings saved!");
 
+    response->setLength();
+    request->send(response);
+}
+
+void WebApiSecurityClass::onAuthenticateGet(AsyncWebServerRequest* request)
+{
+    if (!WebApi.checkCredentials(request)) {
+        return;
+    }
+
+    AsyncJsonResponse* response = new AsyncJsonResponse();
+    JsonObject retMsg = response->getRoot();
+    retMsg[F("type")] = F("success");
+    retMsg[F("message")] = F("Authentication successfull!");
+
     response->setLength();
     request->send(response);
 }
\ No newline at end of file
diff --git a/webapp/package.json b/webapp/package.json
index 4cc42eb..b57fad8 100644
--- a/webapp/package.json
+++ b/webapp/package.json
@@ -14,6 +14,7 @@
     "@popperjs/core": "^2.11.6",
     "bootstrap": "^5.2.2",
     "bootstrap-icons-vue": "^1.8.1",
+    "mitt": "^3.0.0",
     "spark-md5": "^3.0.2",
     "vue": "^3.2.41",
     "vue-router": "^4.1.6"
diff --git a/webapp/src/components/NavBar.vue b/webapp/src/components/NavBar.vue
index ee4fa25..e66760a 100644
--- a/webapp/src/components/NavBar.vue
+++ b/webapp/src/components/NavBar.vue
@@ -73,19 +73,41 @@
                     </li>
                 </ul>
             </div>
+            <form class="d-flex" role="search" v-if="isLogged">
+                <button class="btn btn-outline-danger" @click="signout">Logout</button>
+            </form>
         </div>
     </nav>
 </template>
 
 <script lang="ts">
 import { defineComponent } from 'vue';
+import { logout, isLoggedIn } from '@/utils/authentication';
 import { BIconSun } from 'bootstrap-icons-vue';
 
 export default defineComponent({
     components: {
         BIconSun,
     },
+    data() {
+        return {
+            isLogged: this.isLoggedIn(),
+        }
+    },
+    created() {
+        this.$emitter.on("logged-in", () => {
+            this.isLogged = this.isLoggedIn();
+        });
+    },
     methods: {
+        isLoggedIn,
+        logout,
+        signout(e: Event) {
+            e.preventDefault();
+            this.logout();
+            this.isLogged = this.isLoggedIn();
+            this.$router.push('/');
+        },
         onClick() {
             this.$refs.navbarCollapse && (this.$refs.navbarCollapse as HTMLElement).classList.remove("show");
         }
diff --git a/webapp/src/emitter.d.ts b/webapp/src/emitter.d.ts
new file mode 100644
index 0000000..d083a75
--- /dev/null
+++ b/webapp/src/emitter.d.ts
@@ -0,0 +1,9 @@
+import mitt from 'mitt';
+
+declare module '@vue/runtime-core' {
+    interface ComponentCustomProperties {
+        $emitter: Emitter;
+    }
+}
+
+export { }  // Important! See note.
\ No newline at end of file
diff --git a/webapp/src/main.ts b/webapp/src/main.ts
index 4fdafc3..ecdbf72 100644
--- a/webapp/src/main.ts
+++ b/webapp/src/main.ts
@@ -1,12 +1,16 @@
 import { createApp } from 'vue'
 import App from './App.vue'
 import router from './router'
+import mitt from 'mitt';
 
 import './scss/styles.scss'
 import "bootstrap"
 
 const app = createApp(App)
 
+const emitter = mitt();
+app.config.globalProperties.$emitter = emitter;
+
 app.use(router)
 
 app.mount('#app')
diff --git a/webapp/src/router/index.ts b/webapp/src/router/index.ts
index 9ffdb81..7429f19 100644
--- a/webapp/src/router/index.ts
+++ b/webapp/src/router/index.ts
@@ -13,6 +13,7 @@ import DtuAdminView from '@/views/DtuAdminView.vue'
 import FirmwareUpgradeView from '@/views/FirmwareUpgradeView.vue'
 import ConfigAdminView from '@/views/ConfigAdminView.vue'
 import SecurityAdminView from '@/views/SecurityAdminView.vue'
+import LoginView from '@/views/LoginView.vue'
 
 const router = createRouter({
     history: createWebHistory(import.meta.env.BASE_URL),
@@ -23,6 +24,11 @@ const router = createRouter({
         name: 'Home',
         component: HomeView
     },
+    {
+        path: '/login',
+        name: 'Login',
+        component: LoginView
+    },
     {
         path: '/about',
         name: 'About',
@@ -89,6 +95,23 @@ const router = createRouter({
         component: SecurityAdminView
     }
 ]
-})
+});
+
+router.beforeEach((to, from, next) => {
+    // redirect to login page if not logged in and trying to access a restricted page
+    const publicPages = ['/', '/login', '/about', '/info/network', '/info/system', '/info/ntp', '/info/mqtt',
+        '/settings/network', '/settings/ntp', '/settings/mqtt', '/settings/inverter', '/settings/dtu', '/firmware/upgrade', '/settings/config', ];
+    const authRequired = !publicPages.includes(to.path);
+    const loggedIn = localStorage.getItem('user');
+
+    if (authRequired && !loggedIn) {
+        return next({
+            path: '/login',
+            query: { returnUrl: to.path }
+        });
+    }
+
+    next();
+});
 
 export default router;
\ No newline at end of file
diff --git a/webapp/src/utils/authentication.ts b/webapp/src/utils/authentication.ts
new file mode 100644
index 0000000..fe145da
--- /dev/null
+++ b/webapp/src/utils/authentication.ts
@@ -0,0 +1,78 @@
+export function authHeader(): HeadersInit {
+    // return authorization header with basic auth credentials
+    let user = JSON.parse(localStorage.getItem('user') || "");
+
+    if (user && user.authdata) {
+        return { 'Authorization': 'Basic ' + user.authdata };
+    } else {
+        return {};
+    }
+}
+
+export function logout() {
+    // remove user from local storage to log user out
+    localStorage.removeItem('user');
+}
+
+export function isLoggedIn(): boolean {
+    return (localStorage.getItem('user') != null);
+}
+
+export function login(username: String, password: String) {
+    const requestOptions = {
+        method: 'GET',
+        headers: {
+            'X-Requested-With': 'XMLHttpRequest',
+            'Authorization': 'Basic ' + window.btoa(username + ':' + password)
+        },
+    };
+
+    return fetch('/api/security/authenticate', requestOptions)
+        .then(handleAuthResponse)
+        .then(retVal => {
+            // login successful if there's a user in the response
+            if (retVal) {
+                // store user details and basic auth credentials in local storage
+                // to keep user logged in between page refreshes
+                retVal.authdata = window.btoa(username + ':' + password);
+                localStorage.setItem('user', JSON.stringify(retVal));
+            }
+
+            return retVal;
+        });
+}
+
+export function handleResponse(response: Response) {
+    return response.text().then(text => {
+        const data = text && JSON.parse(text);
+        if (!response.ok) {
+            if (response.status === 401) {
+                // auto logout if 401 response returned from api
+                logout();
+                location.reload();
+            }
+
+            const error = (data && data.message) || response.statusText;
+            return Promise.reject(error);
+        }
+
+        return data;
+    });
+}
+
+function handleAuthResponse(response: Response) {
+    return response.text().then(text => {
+        const data = text && JSON.parse(text);
+        if (!response.ok) {
+            if (response.status === 401) {
+                // auto logout if 401 response returned from api
+                logout();
+            }
+
+            const error = "Invalid credentials";
+            return Promise.reject(error);
+        }
+
+        return data;
+    });
+}
\ No newline at end of file
diff --git a/webapp/src/utils/index.ts b/webapp/src/utils/index.ts
index d96d8ac..7e736d5 100644
--- a/webapp/src/utils/index.ts
+++ b/webapp/src/utils/index.ts
@@ -1,12 +1,19 @@
 import { timestampToString } from './time';
 import { formatNumber } from './number';
+import { login, logout, isLoggedIn } from './authentication';
 
 export {
     timestampToString,
     formatNumber,
+    login,
+    logout,
+    isLoggedIn,
 };
 
 export default {
     timestampToString,
     formatNumber,
+    login,
+    logout,
+    isLoggedIn,
 }
\ No newline at end of file
diff --git a/webapp/src/views/LoginView.vue b/webapp/src/views/LoginView.vue
new file mode 100644
index 0000000..b1c5f48
--- /dev/null
+++ b/webapp/src/views/LoginView.vue
@@ -0,0 +1,88 @@
+<template>
+    <BasePage :title="'Login'" :isLoading="dataLoading">
+        <BootstrapAlert v-model="showAlert" dismissible :variant="alertType">
+            {{ alertMessage }}
+        </BootstrapAlert>
+
+        <div class="card">
+            <div class="card-header text-bg-danger">System Login</div>
+            <div class="card-body">
+
+                <form @submit.prevent="handleSubmit">
+                    <div class="form-group">
+                        <label for="username">Username</label>
+                        <input type="text" v-model="username" name="username" class="form-control"
+                            :class="{ 'is-invalid': submitted && !username }" />
+                        <div v-show="submitted && !username" class="invalid-feedback">Username is required</div>
+                    </div>
+                    <div class="form-group">
+                        <label htmlFor="password">Password</label>
+                        <input type="password" v-model="password" name="password" class="form-control"
+                            :class="{ 'is-invalid': submitted && !password }" />
+                        <div v-show="submitted && !password" class="invalid-feedback">Password is required</div>
+                    </div>
+                    <div class="form-group">
+                        <button class="btn btn-primary" :disabled="dataLoading">Login</button>
+                    </div>
+                </form>
+            </div>
+        </div>
+    </BasePage>
+</template>
+
+<script lang="ts">
+import { defineComponent } from 'vue';
+import router from '@/router';
+import { login } from '@/utils';
+import BasePage from '@/components/BasePage.vue';
+import BootstrapAlert from "@/components/BootstrapAlert.vue";
+
+export default defineComponent({
+    components: {
+        BasePage,
+        BootstrapAlert,
+    },
+    data() {
+        return {
+            dataLoading: false,
+            alertMessage: "",
+            alertType: "info",
+            showAlert: false,
+            returnUrl: '',
+            username: '',
+            password: '',
+            submitted: false,
+        };
+    },
+    created() {
+        // get return url from route parameters or default to '/'
+        this.returnUrl = this.$route.query.returnUrl?.toString() || '/';
+    },
+    methods: {
+        handleSubmit(e: Event) {
+            this.submitted = true;
+            const { username, password } = this;
+
+            // stop here if form is invalid
+            if (!(username && password)) {
+                return;
+            }
+
+            this.dataLoading = true;
+            login(username, password)
+                .then(
+                    () => {
+                        this.$emitter.emit("logged-in");
+                        router.push(this.returnUrl);
+                    },
+                    error => {
+                        this.alertMessage = error;
+                        this.alertType = 'danger';
+                        this.showAlert = true;
+                        this.dataLoading = false;
+                    }
+                )
+        }
+    }
+});
+</script>
\ No newline at end of file
diff --git a/webapp/src/views/SecurityAdminView.vue b/webapp/src/views/SecurityAdminView.vue
index f687817..d557bd8 100644
--- a/webapp/src/views/SecurityAdminView.vue
+++ b/webapp/src/views/SecurityAdminView.vue
@@ -26,8 +26,8 @@
 
                     <div class="alert alert-secondary" role="alert">
                         <b>Hint:</b>
-                        The administrator password is used to connect to the device when in AP mode.
-                        It must be 8..64 characters.
+                        The administrator password is used to access this web interface (user 'admin'), but also to
+                        connect to the device when in AP mode. It must be 8..64 characters.
                     </div>
 
                 </div>
@@ -41,6 +41,7 @@
 import { defineComponent } from 'vue';
 import BasePage from '@/components/BasePage.vue';
 import BootstrapAlert from "@/components/BootstrapAlert.vue";
+import { handleResponse, authHeader } from '@/utils/authentication';
 import type { SecurityConfig } from '@/types/SecurityConfig';
 
 export default defineComponent({
@@ -65,8 +66,8 @@ export default defineComponent({
     methods: {
         getPasswordConfig() {
             this.dataLoading = true;
-            fetch("/api/security/password")
-                .then((response) => response.json())
+            fetch("/api/security/password", { headers: authHeader() })
+                .then(handleResponse)
                 .then(
                     (data) => {
                         this.securityConfigList = data;
@@ -90,15 +91,10 @@ export default defineComponent({
 
             fetch("/api/security/password", {
                 method: "POST",
+                headers: authHeader(),
                 body: formData,
             })
-                .then(function (response) {
-                    if (response.status != 200) {
-                        throw response.status;
-                    } else {
-                        return response.json();
-                    }
-                })
+                .then(handleResponse)
                 .then(
                     (response) => {
                         this.alertMessage = response.message;
diff --git a/webapp/yarn.lock b/webapp/yarn.lock
index 78e37b1..f6ef1d2 100644
--- a/webapp/yarn.lock
+++ b/webapp/yarn.lock
@@ -1474,6 +1474,11 @@ minimatch@^5.1.0:
   dependencies:
     brace-expansion "^2.0.1"
 
+mitt@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/mitt/-/mitt-3.0.0.tgz#69ef9bd5c80ff6f57473e8d89326d01c414be0bd"
+  integrity sha512-7dX2/10ITVyqh4aOSVI9gdape+t9l2/8QxHrFmUXu4EEUpdlxl6RudZUPZoc+zuY2hk1j7XxVroIVIan/pD/SQ==
+
 ms@2.1.2:
   version "2.1.2"
   resolved "https://registry.yarnpkg.com/ms/-/ms-2.1.2.tgz#d09d1f357b443f493382a8eb3ccd183872ae6009"