diff --git a/locales/de.json b/locales/de.json
index 93fe796..23dc9b1 100644
--- a/locales/de.json
+++ b/locales/de.json
@@ -4,7 +4,29 @@
     "cancel": "Abbrechen",
     "search": "Suchen",
     "reset": "Reset",
-    "dashboard": "Dashboard"
+    "dashboard": "Dashboard",
+    "logout": "Logout",
+    "title":"Titel",
+    "firstname":"Vorname",
+    "lastname":"Nachname",
+    "username":"Username",
+    "role":"Rolle",
+    "action":"Aktionen",
+    "status":"Status",
+    "you":"Du Selbst",
+    "newuser":"Neuer benutzer",
+    "inactive":"inaktive",
+    "active":"aktive",
+    "closed":"gesperrt",
+    "filter":"Filtern",
+    "yearcash":"Jahresumsatz",
+    "monthcash":"Monatsumsatz",
+    "quartalcash":"Quartalsumsatz",
+    "year":"Jahr",
+    "nodata":"keine Daten",
+    "month":"Monat",
+    "patientcash":"Umsatz pro Patient",
+    "patient":"Patient"
   },
   "sidebar": {
     "patients": "Patienten",
@@ -19,8 +41,40 @@
     "waitingRoom": "Wartezimmer-Monitor",
     "noWaitingPatients": "Keine Patienten im Wartezimmer."
   },
+
   "adminSidebar": {
     "users": "Userverwaltung",
-    "database": "Datenbankverwaltung"
+    "database": "Datenbankverwaltung",
+    "user":"Benutzer",
+    "invocieoverview":"Rechnungsübersicht",
+    "seriennumber":"Seriennummer",
+    "databasetable":"Datenbank"
+  },
+
+  "adminuseroverview": {
+    "useroverview": "Benutzerübersicht",
+    "usermanagement": "Benutzer Verwaltung",
+    "user":"Benutzer",
+    "invocieoverview":"Rechnungsübersicht",
+    "seriennumber":"Seriennummer",
+    "databasetable":"Datenbank"
+  },
+
+  "seriennumber": {
+    "seriennumbertitle": "Seriennummer eingeben",
+    "seriennumbertext": "Bitte gib deine Lizenz-Seriennummer ein um die Software dauerhaft freizuschalten.",
+    "seriennumbershort":"Seriennummer (AAAAA-AAAAA-AAAAA-AAAAA)",
+    "seriennumberdeclaration":"Nur Buchstaben + Zahlen. Format: 4×5 Zeichen, getrennt mit „-“. ",
+    "saveseriennumber":"Seriennummer Speichern"
+  },
+
+  "databaseoverview": {
+    "title": "Datenbank Konfiguration",
+    "text":"Hier kannst du die DB-Verbindung testen und speichern. ",
+    "host": "Host",
+    "port":"Port",
+    "database":"Datenbank",
+    "password":"Password",
+    "connectiontest":"Verbindung testen"
   }
 }
diff --git a/locales/es.json b/locales/es.json
index 0b6cd23..6fb5da9 100644
--- a/locales/es.json
+++ b/locales/es.json
@@ -4,7 +4,29 @@
     "cancel": "Cancelar",
     "search": "Buscar",
     "reset": "Resetear",
-    "dashboard": "Panel"
+    "dashboard": "Panel",
+    "logout": "cerrar sesión",
+    "title":"Título",
+    "firstname":"Nombre",
+    "lastname":"apellido",
+    "username":"Nombre de usuario",
+    "role":"desempeñar",
+    "action":"acción",
+    "status":"Estado",
+    "you":"su mismo",
+    "newuser":"Nuevo usuario",
+    "inactive":"inactivo",
+    "active":"activo",
+    "closed":"bloqueado",
+    "filter":"Filtro",
+    "yearcash":"volumen de negocios anual",
+    "monthcash":"volumen de negocios mensual",
+    "quartalcash":"volumen de negocios trimestral",
+    "year":"ano",
+    "nodata":"sin datos",
+    "month":"mes",
+    "patientcash":"Ingresos por paciente",
+    "patient":"paciente"
   },
   "sidebar": {
     "patients": "Pacientes",
@@ -22,6 +44,37 @@
 
   "adminSidebar": {
     "users": "Administración de usuarios",
-    "database": "Administración de base de datos"
+    "database": "Administración de base de datos",
+    "user":"usuario",
+    "invocieoverview":"Resumen de facturas",
+    "seriennumber":"número de serie",
+    "databasetable":"base de datos"
+  },
+
+  "adminuseroverview": {
+    "useroverview": "Resumen de usuarios",
+    "usermanagement": "Administración de usuarios",
+    "user":"usuario",
+    "invocieoverview":"Resumen de facturas",
+    "seriennumber":"número de serie",
+    "databasetable":"base de datos"
+  },
+
+  "seriennumber": {
+    "seriennumbertitle": "Introduce el número de serie",
+    "seriennumbertext": "Introduce el número de serie de tu licencia para activar el software de forma permanente.",
+    "seriennumbershort":"Número de serie (AAAAA-AAAAA-AAAAA-AAAAA)",
+    "seriennumberdeclaration":"Solo letras y números. Formato: 4×5 caracteres, separados por «-». ",
+    "saveseriennumber":"Guardar número de serie"
+  },
+
+  "databaseoverview": {
+    "title": "Configuración de la base de datos",
+    "host": "Host",
+    "port":"Puerto",
+    "database":"Base de datos",
+    "password":"Contraseña",
+    "connectiontest":"Probar conexión",
+    "text":"Aquí puedes probar y guardar la conexión a la base de datos. "
   }
 }
diff --git a/views/admin/admin_invoice_overview.ejs b/views/admin/admin_invoice_overview.ejs
index 5dfeaf0..7406ffc 100644
--- a/views/admin/admin_invoice_overview.ejs
+++ b/views/admin/admin_invoice_overview.ejs
@@ -1,7 +1,7 @@
 <!-- ✅ Header -->
 <%- include("../partials/page-header", {
   user,
-  title: "Rechnungsübersicht",
+  title: t.adminSidebar.invocieoverview,
   subtitle: "",
   showUserName: true
 }) %>
@@ -33,7 +33,7 @@
       </div>
 
       <div class="col-auto">
-        <button class="btn btn-outline-secondary">Filtern</button>
+        <button class="btn btn-outline-secondary"><%= t.global.filter %></button>
       </div>
     </form>
 
@@ -43,12 +43,12 @@
       <!-- JAHRESUMSATZ -->
       <div class="col-xl-3 col-lg-6">
         <div class="card h-100">
-          <div class="card-header fw-semibold">Jahresumsatz</div>
+          <div class="card-header fw-semibold"><%= t.global.yearcash%></div>
           <div class="card-body p-0">
             <table class="table table-sm table-striped mb-0">
               <thead>
                 <tr>
-                  <th>Jahr</th>
+                  <th><%= t.global.year%></th>
                   <th class="text-end">€</th>
                 </tr>
               </thead>
@@ -56,7 +56,7 @@
                 <% if (!yearly || yearly.length === 0) { %>
                   <tr>
                     <td colspan="2" class="text-center text-muted">
-                      Keine Daten
+                      <%= t.global.nodata%>
                     </td>
                   </tr>
                 <% } %>
@@ -78,12 +78,12 @@
       <!-- QUARTALSUMSATZ -->
       <div class="col-xl-3 col-lg-6">
         <div class="card h-100">
-          <div class="card-header fw-semibold">Quartalsumsatz</div>
+          <div class="card-header fw-semibold"><%= t.global.quartalcash%></div>
           <div class="card-body p-0">
             <table class="table table-sm table-striped mb-0">
               <thead>
                 <tr>
-                  <th>Jahr</th>
+                  <th><%= t.global.year%></th>
                   <th>Q</th>
                   <th class="text-end">€</th>
                 </tr>
@@ -92,7 +92,7 @@
                 <% if (!quarterly || quarterly.length === 0) { %>
                   <tr>
                     <td colspan="3" class="text-center text-muted">
-                      Keine Daten
+                      <%= t.global.nodata%>
                     </td>
                   </tr>
                 <% } %>
@@ -115,12 +115,12 @@
       <!-- MONATSUMSATZ -->
       <div class="col-xl-3 col-lg-6">
         <div class="card h-100">
-          <div class="card-header fw-semibold">Monatsumsatz</div>
+          <div class="card-header fw-semibold"><%= t.global.monthcash%></div>
           <div class="card-body p-0">
             <table class="table table-sm table-striped mb-0">
               <thead>
                 <tr>
-                  <th>Monat</th>
+                  <th><%= t.global.month%></th>
                   <th class="text-end">€</th>
                 </tr>
               </thead>
@@ -128,7 +128,7 @@
                 <% if (!monthly || monthly.length === 0) { %>
                   <tr>
                     <td colspan="2" class="text-center text-muted">
-                      Keine Daten
+                      <%= t.global.nodata%>
                     </td>
                   </tr>
                 <% } %>
@@ -150,7 +150,7 @@
       <!-- UMSATZ PRO PATIENT -->
       <div class="col-xl-3 col-lg-6">
         <div class="card h-100">
-          <div class="card-header fw-semibold">Umsatz pro Patient</div>
+          <div class="card-header fw-semibold"><%= t.global.patientcash%></div>
           <div class="card-body p-2">
 
             <!-- Suche -->
@@ -166,20 +166,20 @@
                 placeholder="Patient suchen..."
               />
 
-              <button class="btn btn-sm btn-outline-primary">Suchen</button>
+              <button class="btn btn-sm btn-outline-primary"><%= t.global.search%></button>
 
               <a
                 href="/admin/invoices?fromYear=<%= fromYear %>&toYear=<%= toYear %>"
                 class="btn btn-sm btn-outline-secondary"
               >
-                Reset
+                <%= t.global.reset%>
               </a>
             </form>
 
             <table class="table table-sm table-striped mb-0">
               <thead>
                 <tr>
-                  <th>Patient</th>
+                  <th><%= t.global.patient%></th>
                   <th class="text-end">€</th>
                 </tr>
               </thead>
@@ -187,7 +187,7 @@
                 <% if (!patients || patients.length === 0) { %>
                   <tr>
                     <td colspan="2" class="text-center text-muted">
-                      Keine Daten
+                      <%= t.global.nodata%>
                     </td>
                   </tr>
                 <% } %>
diff --git a/views/admin/database.ejs b/views/admin/database.ejs
index 8b4f9bb..5a5650b 100644
--- a/views/admin/database.ejs
+++ b/views/admin/database.ejs
@@ -9,7 +9,7 @@
     <!-- ✅ HEADER (wie Dashboard) -->
     <%- include("../partials/page-header", {
       user,
-      title: "Datenbankverwaltung",
+      title: t.adminSidebar.database,
       subtitle: "",
       showUserName: true,
       hideDashboardButton: true
@@ -29,18 +29,18 @@
               <div class="card-body">
 
                 <h4 class="mb-3">
-                  <i class="bi bi-sliders"></i> Datenbank Konfiguration
+                  <i class="bi bi-sliders"></i> <%= t.databaseoverview.title%>
                 </h4>
 
                 <p class="text-muted mb-4">
-                  Hier kannst du die DB-Verbindung testen und speichern.
+                  <%= t.databaseoverview.tittexte%>
                 </p>
 
                 <!-- ✅ TEST + SPEICHERN -->
                 <form method="POST" action="/admin/database/test" class="row g-3 mb-3" autocomplete="off">
 
                   <div class="col-md-6">
-                    <label class="form-label">Host / IP</label>
+                    <label class="form-label"><%= t.databaseoverview.host%> / IP</label>
                     <input
                       type="text"
                       name="host"
@@ -52,7 +52,7 @@
                   </div>
 
                   <div class="col-md-3">
-                    <label class="form-label">Port</label>
+                    <label class="form-label"><%= t.databaseoverview.port%></label>
                     <input
                       type="number"
                       name="port"
@@ -64,7 +64,7 @@
                   </div>
 
                   <div class="col-md-3">
-                    <label class="form-label">Datenbank</label>
+                    <label class="form-label"><%= t.databaseoverview.database%></label>
                     <input
                       type="text"
                       name="name"
@@ -76,7 +76,7 @@
                   </div>
 
                   <div class="col-md-6">
-                    <label class="form-label">Benutzer</label>
+                    <label class="form-label"><%= t.global.user%></label>
                     <input
                       type="text"
                       name="user"
@@ -88,7 +88,7 @@
                   </div>
 
                   <div class="col-md-6">
-                    <label class="form-label">Passwort</label>
+                    <label class="form-label"><%= t.databaseoverview.password%></label>
                     <input
                       type="password"
                       name="password"
@@ -102,7 +102,7 @@
                   <div class="col-12 d-flex flex-wrap gap-2">
 
                     <button type="submit" class="btn btn-outline-primary">
-                      <i class="bi bi-plug"></i> Verbindung testen
+                      <i class="bi bi-plug"></i> <%= t.databaseoverview.connectiontest%>
                     </button>
 
                     <button
@@ -110,7 +110,7 @@
                       class="btn btn-success"
                       formaction="/admin/database"
                     >
-                      <i class="bi bi-save"></i> Speichern
+                      <i class="bi bi-save"></i> <%= t.global.save%>
                     </button>
 
                   </div>
diff --git a/views/admin_users.ejs b/views/admin_users.ejs
index 7f10057..bfbd02e 100644
--- a/views/admin_users.ejs
+++ b/views/admin_users.ejs
@@ -5,7 +5,7 @@
     <!-- ✅ HEADER -->
     <%- include("partials/page-header", {
       user,
-      title: "User Verwaltung",
+      title: t.adminuseroverview.usermanagement,
       subtitle: "",
       showUserName: true
     }) %>
@@ -20,11 +20,11 @@
           <div class="card-body">
 
             <div class="d-flex align-items-center justify-content-between mb-3">
-              <h4 class="mb-0">Benutzerübersicht</h4>
+              <h4 class="mb-0"><%= t.adminuseroverview.useroverview %></h4>
 
               <a href="/admin/create-user" class="btn btn-primary">
                 <i class="bi bi-plus-circle"></i>
-                Neuer Benutzer
+                <%= t.global.newuser %>
               </a>
             </div>
 
@@ -34,13 +34,13 @@
                 <thead>
                   <tr>
                     <th>ID</th>
-                    <th>Titel</th>
-                    <th>Vorname</th>
-                    <th>Nachname</th>
-                    <th>Username</th>
-                    <th>Rolle</th>
-                    <th class="text-center">Status</th>
-                    <th>Aktionen</th>
+                    <th><%= t.global.title %></th>
+                    <th><%= t.global.firstname %></th>
+                    <th><%= t.global.lastname %></th>
+                    <th><%= t.global.username %></th>
+                    <th><%= t.global.role %></th>
+                    <th class="text-center"><%= t.global.status %></th>
+                    <th><%= t.global.action %></th>
                   </tr>
                 </thead>
 
@@ -79,11 +79,11 @@
 
                         <td class="text-center">
                           <% if (u.active === 0) { %>
-                            <span class="badge bg-secondary">Inaktiv</span>
+                            <span class="badge bg-secondary"><%= t.global.inactive %></span>
                           <% } else if (u.lock_until && new Date(u.lock_until) > new Date()) { %>
-                            <span class="badge bg-danger">Gesperrt</span>
+                            <span class="badge bg-danger"><%= t.global.closed %></span>
                           <% } else { %>
-                            <span class="badge bg-success">Aktiv</span>
+                            <span class="badge bg-success"><%= t.global.active %></span>
                           <% } %>
                         </td>
 
@@ -109,7 +109,7 @@
                               </button>
                             </form>
                           <% } else { %>
-                            <span class="badge bg-light text-dark border">👤 Du selbst</span>
+                            <span class="badge bg-light text-dark border">👤 <%= t.global.you %></span>
                           <% } %>
 
                         </td>
diff --git a/views/partials/admin-sidebar.ejs b/views/partials/admin-sidebar.ejs
index 29aaf7c..65ea731 100644
--- a/views/partials/admin-sidebar.ejs
+++ b/views/partials/admin-sidebar.ejs
@@ -32,7 +32,7 @@
       class="nav-item <%= active === 'users' ? 'active' : '' %> <%= lockClass(isAdmin) %>"
       title="<%= isAdmin ? '' : 'Nur Admin' %>"
     >
-      <i class="bi bi-people"></i> Benutzer
+      <i class="bi bi-people"></i> <%= t.adminSidebar.user %>
       <% if (!isAdmin) { %>
         <span style="margin-left:auto;"><i class="bi bi-lock-fill"></i></span>
       <% } %>
@@ -44,7 +44,7 @@
       class="nav-item <%= active === 'invoice_overview' ? 'active' : '' %> <%= lockClass(isAdmin) %>"
       title="<%= isAdmin ? '' : 'Nur Admin' %>"
     >
-      <i class="bi bi-calculator"></i> Rechnungsübersicht
+      <i class="bi bi-calculator"></i> <%= t.adminSidebar.invocieoverview %>
       <% if (!isAdmin) { %>
         <span style="margin-left:auto;"><i class="bi bi-lock-fill"></i></span>
       <% } %>
@@ -57,7 +57,7 @@
       class="nav-item <%= active === 'serialnumber' ? 'active' : '' %> <%= lockClass(isAdmin) %>"
       title="<%= isAdmin ? '' : 'Nur Admin' %>"
     >
-      <i class="bi bi-key"></i> Seriennummer
+      <i class="bi bi-key"></i> <%= t.adminSidebar.seriennumber %>
       <% if (!isAdmin) { %>
         <span style="margin-left:auto;"><i class="bi bi-lock-fill"></i></span>
       <% } %>
@@ -69,7 +69,7 @@
       class="nav-item <%= active === 'database' ? 'active' : '' %> <%= lockClass(isAdmin) %>"
       title="<%= isAdmin ? '' : 'Nur Admin' %>"
     >
-      <i class="bi bi-hdd-stack"></i> Datenbank
+      <i class="bi bi-hdd-stack"></i> <%= t.adminSidebar.databasetable %>
       <% if (!isAdmin) { %>
         <span style="margin-left:auto;"><i class="bi bi-lock-fill"></i></span>
       <% } %>
diff --git a/views/partials/sidebar.ejs b/views/partials/sidebar.ejs
index 192273f..c64e7fb 100644
--- a/views/partials/sidebar.ejs
+++ b/views/partials/sidebar.ejs
@@ -58,7 +58,7 @@
     class="nav-item <%= active === 'patients' ? 'active' : '' %> <%= lockClass(canDoctorAndStaff) %>"
     title="<%= canDoctorAndStaff ? '' : 'Nur Arzt + Mitarbeiter' %>"
   >
-    <i class="bi bi-people"></i> <%= t.sidebar.patients %>
+    <i class="bi bi-people"></i> <%= t.sidebar.patients %> 
     <% if (!canDoctorAndStaff) { %>
       <span style="margin-left:auto;"><i class="bi bi-lock-fill"></i></span>
     <% } %>
@@ -116,7 +116,7 @@
 
   <!-- ✅ Logout -->
   <a href="/logout" class="nav-item">
-    <i class="bi bi-box-arrow-right"></i> Logout
+    <i class="bi bi-box-arrow-right"></i> <%= t.sidebar.logout %>
   </a>
 
 </div>
diff --git a/views/serial_number_admin.ejs b/views/serial_number_admin.ejs
index 73affc7..317d45d 100644
--- a/views/serial_number_admin.ejs
+++ b/views/serial_number_admin.ejs
@@ -15,10 +15,10 @@
 
     <div class="content" style="max-width:650px; margin:30px auto;">
 
-      <h2>🔑 Seriennummer eingeben</h2>
+      <h2>🔑 <%= t.seriennumber.seriennumbertitle %></h2>
 
       <p style="color:#777;">
-        Bitte gib deine Lizenz-Seriennummer ein um die Software dauerhaft freizuschalten.
+        <%= t.seriennumber.seriennumbertext %>
       </p>
 
       <% if (error) { %>
@@ -31,7 +31,7 @@
 
       <form method="POST" action="/admin/serial-number" style="max-width: 500px;">
         <div class="form-group">
-          <label>Seriennummer (AAAAA-AAAAA-AAAAA-AAAAA)</label>
+          <label><%= t.seriennumber.seriennumbershort %></label>
           <input
             type="text"
             name="serial_number"
@@ -42,12 +42,12 @@
             required
           />
           <small style="color:#777; display:block; margin-top:6px;">
-            Nur Buchstaben + Zahlen. Format: 4×5 Zeichen, getrennt mit „-“.
+            <%= t.seriennumber.seriennumberdeclaration %>
           </small>
         </div>
 
         <button class="btn btn-primary" style="margin-top: 15px;">
-          Seriennummer speichern
+          <%= t.seriennumber.saveseriennumber %>
         </button>
       </form>