diff --git a/backend/src/routes/auth/auth-authenticated.ts b/backend/src/routes/auth/auth-authenticated.ts
index b7626c0..e54f01f 100644
--- a/backend/src/routes/auth/auth-authenticated.ts
+++ b/backend/src/routes/auth/auth-authenticated.ts
@@ -1,11 +1,60 @@
 import { FastifyInstance } from "fastify"
 import bcrypt from "bcrypt"
 import { eq } from "drizzle-orm"
+import jwt from "jsonwebtoken"
+import { secrets } from "../../utils/secrets"
 
 import { authUsers } from "../../../db/schema"  // wichtig: Drizzle Schema importieren!
 
 export default async function authRoutesAuthenticated(server: FastifyInstance) {
 
+    server.post("/auth/refresh", {
+        schema: {
+            tags: ["Auth"],
+            summary: "Refresh JWT for current authenticated user",
+            response: {
+                200: {
+                    type: "object",
+                    properties: {
+                        token: { type: "string" },
+                    },
+                    required: ["token"],
+                },
+                401: {
+                    type: "object",
+                    properties: {
+                        error: { type: "string" },
+                    },
+                    required: ["error"],
+                },
+            },
+        },
+    }, async (req, reply) => {
+        if (!req.user?.user_id) {
+            return reply.code(401).send({ error: "Unauthorized" })
+        }
+
+        const token = jwt.sign(
+            {
+                user_id: req.user.user_id,
+                email: req.user.email,
+                tenant_id: req.user.tenant_id,
+            },
+            secrets.JWT_SECRET!,
+            { expiresIn: "6h" }
+        )
+
+        reply.setCookie("token", token, {
+            path: "/",
+            httpOnly: true,
+            sameSite: process.env.NODE_ENV === "production" ? "none" : "lax",
+            secure: process.env.NODE_ENV === "production",
+            maxAge: 60 * 60 * 6,
+        })
+
+        return { token }
+    })
+
     server.post("/auth/password/change", {
         schema: {
             tags: ["Auth"],
diff --git a/backend/src/routes/auth/auth.ts b/backend/src/routes/auth/auth.ts
index dd4eb14..7d7881e 100644
--- a/backend/src/routes/auth/auth.ts
+++ b/backend/src/routes/auth/auth.ts
@@ -137,7 +137,7 @@ export default async function authRoutes(server: FastifyInstance) {
             httpOnly: true,
             sameSite: process.env.NODE_ENV === "production" ? "none" : "lax",
             secure: process.env.NODE_ENV === "production",
-            maxAge: 60 * 60 * 3,
+            maxAge: 60 * 60 * 6,
         });
 
         return { token };
diff --git a/frontend/components/SessionRefreshModal.vue b/frontend/components/SessionRefreshModal.vue
new file mode 100644
index 0000000..b5b9182
--- /dev/null
+++ b/frontend/components/SessionRefreshModal.vue
@@ -0,0 +1,43 @@
+<script setup lang="ts">
+const auth = useAuthStore()
+
+const remainingMinutes = computed(() => Math.floor(auth.sessionWarningRemainingSeconds / 60))
+const remainingSeconds = computed(() => auth.sessionWarningRemainingSeconds % 60)
+const remainingTimeLabel = computed(() => `${remainingMinutes.value}:${String(remainingSeconds.value).padStart(2, "0")}`)
+
+const onRefresh = async () => {
+  await auth.refreshSession()
+}
+
+const onLogout = async () => {
+  auth.sessionWarningVisible = false
+  await auth.logout()
+}
+</script>
+
+<template>
+  <UModal v-model="auth.sessionWarningVisible" prevent-close>
+    <UCard>
+      <template #header>
+        <h3 class="text-lg font-semibold">Sitzung läuft bald ab</h3>
+      </template>
+
+      <p class="text-sm text-gray-600 dark:text-gray-300">
+        Deine Sitzung endet in
+        <span class="font-semibold">{{ remainingTimeLabel }}</span>.
+        Bitte bestätige, um eingeloggt zu bleiben.
+      </p>
+
+      <template #footer>
+        <div class="flex justify-end gap-2">
+          <UButton variant="outline" color="gray" @click="onLogout">
+            Abmelden
+          </UButton>
+          <UButton color="primary" @click="onRefresh">
+            Eingeloggt bleiben
+          </UButton>
+        </div>
+      </template>
+    </UCard>
+  </UModal>
+</template>
diff --git a/frontend/layouts/default.vue b/frontend/layouts/default.vue
index 0d8247d..028353c 100644
--- a/frontend/layouts/default.vue
+++ b/frontend/layouts/default.vue
@@ -5,6 +5,7 @@ import GlobalMessages from "~/components/GlobalMessages.vue";
 import TenantDropdown from "~/components/TenantDropdown.vue";
 import LabelPrinterButton from "~/components/LabelPrinterButton.vue";
 import {useCalculatorStore} from '~/stores/calculator'
+import SessionRefreshModal from "~/components/SessionRefreshModal.vue";
 
 const dataStore = useDataStore()
 const colorMode = useColorMode()
@@ -130,6 +131,7 @@ const footerLinks = computed(() => [
 
 <template>
   <div v-if="!auth.loading">
+    <SessionRefreshModal />
     <div v-if="auth.activeTenantData?.locked === 'maintenance_tenant'">
       <UContainer class="min-h-screen flex items-center justify-center bg-gray-50 dark:bg-gray-900">
         <UCard class="max-w-lg text-center p-10">
@@ -315,4 +317,4 @@ const footerLinks = computed(() => [
 
   </div>
 
-</template>
\ No newline at end of file
+</template>
diff --git a/frontend/stores/auth.ts b/frontend/stores/auth.ts
index 308831e..05610e8 100644
--- a/frontend/stores/auth.ts
+++ b/frontend/stores/auth.ts
@@ -12,13 +12,129 @@ export const useAuthStore = defineStore("auth", {
         activeTenantData: null as any,
         loading: true as boolean,
         notLoggedIn: true,
+        sessionWarningVisible: false,
+        sessionWarningRemainingSeconds: 0,
+        sessionWarningLeadMs: 5 * 60 * 1000,
+        sessionWarningTimer: null as ReturnType<typeof setTimeout> | null,
+        sessionLogoutTimer: null as ReturnType<typeof setTimeout> | null,
+        sessionCountdownTimer: null as ReturnType<typeof setInterval> | null,
     }),
 
     actions: {
-        async persist(token) {
+        decodeTokenExpiryMs(token: string) {
+            try {
+                const parts = token.split(".")
+                if (parts.length < 2) return null
+
+                const payload = JSON.parse(atob(parts[1].replace(/-/g, "+").replace(/_/g, "/")))
+                if (!payload?.exp) return null
+
+                return Number(payload.exp) * 1000
+            } catch (err) {
+                console.error("Could not decode token expiry", err)
+                return null
+            }
+        },
+
+        clearSessionTimers() {
+            if (!process.client) return
+
+            if (this.sessionWarningTimer) {
+                clearTimeout(this.sessionWarningTimer)
+                this.sessionWarningTimer = null
+            }
+
+            if (this.sessionLogoutTimer) {
+                clearTimeout(this.sessionLogoutTimer)
+                this.sessionLogoutTimer = null
+            }
+
+            if (this.sessionCountdownTimer) {
+                clearInterval(this.sessionCountdownTimer)
+                this.sessionCountdownTimer = null
+            }
+        },
+
+        startSessionCountdown(expiresAtMs: number) {
+            if (!process.client) return
+
+            if (this.sessionCountdownTimer) {
+                clearInterval(this.sessionCountdownTimer)
+            }
+
+            this.sessionCountdownTimer = setInterval(() => {
+                const remaining = Math.max(0, Math.ceil((expiresAtMs - Date.now()) / 1000))
+                this.sessionWarningRemainingSeconds = remaining
+
+                if (remaining <= 0 && this.sessionCountdownTimer) {
+                    clearInterval(this.sessionCountdownTimer)
+                    this.sessionCountdownTimer = null
+                }
+            }, 1000)
+        },
+
+        openSessionWarning(expiresAtMs: number) {
+            this.sessionWarningVisible = true
+            this.sessionWarningRemainingSeconds = Math.max(0, Math.ceil((expiresAtMs - Date.now()) / 1000))
+            this.startSessionCountdown(expiresAtMs)
+        },
+
+        scheduleSessionTimers(token?: string | null) {
+            if (!process.client) return
+
+            const tokenToUse = token || useCookie("token").value
+
+            this.clearSessionTimers()
+            this.sessionWarningVisible = false
+            this.sessionWarningRemainingSeconds = 0
+
+            if (!tokenToUse) return
+
+            const expiresAtMs = this.decodeTokenExpiryMs(tokenToUse)
+            if (!expiresAtMs) return
+
+            const now = Date.now()
+            const msUntilLogout = expiresAtMs - now
+
+            if (msUntilLogout <= 0) {
+                void this.logout()
+                return
+            }
+
+            this.sessionLogoutTimer = setTimeout(() => {
+                this.sessionWarningVisible = false
+                void this.logout()
+            }, msUntilLogout)
+
+            const msUntilWarning = msUntilLogout - this.sessionWarningLeadMs
+
+            if (msUntilWarning <= 0) {
+                this.openSessionWarning(expiresAtMs)
+                return
+            }
+
+            this.sessionWarningTimer = setTimeout(() => {
+                this.openSessionWarning(expiresAtMs)
+            }, msUntilWarning)
+        },
+
+        setToken(token: string | null) {
+            useCookie("token").value = token
+
+            if (!token) {
+                this.clearSessionTimers()
+                this.sessionWarningVisible = false
+                this.sessionWarningRemainingSeconds = 0
+                return
+            }
+
+            this.scheduleSessionTimers(token)
+        },
+
+        async persist(token: string | null) {
 
             console.log("On Web")
-            useCookie("token").value = token // persistieren
+            this.setToken(token)
 
         },
 
@@ -74,8 +190,7 @@ export const useAuthStore = defineStore("auth", {
                 console.log("Token: " + token)
 
                 // 1. WICHTIG: Token sofort ins Cookie schreiben, damit es persistiert wird
-                const tokenCookie = useCookie("token")
-                tokenCookie.value = token
+                this.setToken(token)
 
                 // 2. User Daten laden
                 await this.fetchMe(token)
@@ -112,19 +227,22 @@ export const useAuthStore = defineStore("auth", {
             this.resetState()
 
             // Token löschen
-            useCookie("token").value = null
+            this.setToken(null)
 
             // Nur beim expliziten Logout navigieren wir
             navigateTo("/login")
         },
 
         resetState() {
+            this.clearSessionTimers()
             this.user = null
             this.permissions = []
             this.profile = null
             this.activeTenant = null
             this.tenants = []
             this.activeTenantData = null
+            this.sessionWarningVisible = false
+            this.sessionWarningRemainingSeconds = 0
         },
 
         async fetchMe(jwt= null) {
@@ -162,6 +280,8 @@ export const useAuthStore = defineStore("auth", {
                     this.activeTenantData = me.tenants.find(i => i.id === me.activeTenant)
                 }
 
+                this.scheduleSessionTimers(tokenToUse)
+
                 console.log(this)
 
             } catch (err: any) {
@@ -170,12 +290,27 @@ export const useAuthStore = defineStore("auth", {
 
                 // Stattdessen nur den State sauber machen und Token löschen
                 this.resetState()
-                useCookie("token").value = null
+                this.setToken(null)
 
                 // Wir werfen den Fehler nicht weiter, damit initStore normal durchläuft
             }
         },
 
+        async refreshSession() {
+            try {
+                const { token } = await useNuxtApp().$api("/api/auth/refresh", {
+                    method: "POST",
+                })
+
+                this.setToken(token)
+                await this.fetchMe(token)
+                this.sessionWarningVisible = false
+            } catch (err) {
+                console.error("JWT refresh failed", err)
+                await this.logout()
+            }
+        },
+
         async switchTenant(tenant_id: string) {
             console.log("Auth switchTenant")
             this.loading = true
@@ -188,7 +323,7 @@ export const useAuthStore = defineStore("auth", {
             const {token} = res
 
 
-            useCookie("token").value = token // persistieren
+            this.setToken(token)
 
 
             await this.init(token)
@@ -198,4 +333,4 @@ export const useAuthStore = defineStore("auth", {
             return this.permissions.includes(key)
         }
     }
-})
\ No newline at end of file
+})