Initial commit: Mail service with Brevo SMTP

- Express server with REST API for sending emails - SQLite database for persistent email history - Web interface with form (recipient, CC, subject, text/HTML) - Email footer with embedded image (CID attachment) - Nodemailer configured for Brevo SMTP relay Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
2026-01-16 21:24:32 +00:00
parent b8f5847dca
commit c96aacbae5
12 changed files with 2161 additions and 0 deletions
--- a/.env.example
+++ b/.env.example
@@ -0,0 +1,14 @@
+# Server
+PORT=3000
+
+# Email Configuration
+MAIL_PROVIDER=smtp
+MAIL_FROM_EMAIL=noreply@example.com
+MAIL_FROM_NAME=Secure Portal
+
+# SMTP (Brevo)
+SMTP_HOST=smtp-relay.brevo.com
+SMTP_PORT=587
+SMTP_USER=your-email@example.com
+SMTP_PASSWORD=your-smtp-password
+SMTP_SECURE=false
--- a/.gitignore
+++ b/.gitignore
@@ -0,0 +1,3 @@
+node_modules/
+.env
+data/*.db
--- a/assets/homeicon.png
+++ b/assets/homeicon.png
--- a/docs/plans/2026-01-16-mail-service-design.md
+++ b/docs/plans/2026-01-16-mail-service-design.md
@@ -0,0 +1,104 @@
+# Mail-Service Design
+
+**Datum:** 2026-01-16
+**Status:** Genehmigt
+
+## Übersicht
+
+Weboberfläche zum Testen des Mail-Versands über Brevo (SMTP). Node.js-basiert mit persistenter Historie.
+
+## Technologie-Stack
+
+- **Backend:** Node.js, Express
+- **Mail:** Nodemailer
+- **Datenbank:** SQLite (better-sqlite3)
+- **Frontend:** HTML, CSS, Vanilla JS
+
+## Projektstruktur
+
+```
+mail-service/
+├── .env                    # Konfiguration (SMTP, Port)
+├── .env.example            # Vorlage ohne sensible Daten
+├── package.json
+├── src/
+│   ├── server.js           # Express-Server, Routen
+│   ├── mailer.js           # Nodemailer-Konfiguration
+│   └── database.js         # SQLite-Setup und Queries
+├── public/
+│   ├── index.html          # Hauptseite mit Formular
+│   ├── style.css           # Styling
+│   └── script.js           # Frontend-Logik
+└── data/
+    └── emails.db           # SQLite-Datenbank
+```
+
+## Datenbank-Schema
+
+**Tabelle `emails`:**
+
+| Spalte | Typ | Beschreibung |
+|--------|-----|--------------|
+| id | INTEGER | Primary Key, Auto-Increment |
+| to_email | TEXT | Empfänger-Adresse |
+| cc_email | TEXT | CC-Adresse (optional) |
+| subject | TEXT | Betreff |
+| body | TEXT | Nachrichteninhalt |
+| is_html | INTEGER | 0 = Text, 1 = HTML |
+| status | TEXT | "success" oder "failed" |
+| error_message | TEXT | Fehlermeldung falls fehlgeschlagen |
+| created_at | TEXT | ISO-Timestamp |
+
+## API-Endpunkte
+
+| Methode | Route | Beschreibung |
+|---------|-------|--------------|
+| GET | `/` | Weboberfläche (index.html) |
+| POST | `/api/send` | Mail versenden |
+| GET | `/api/history` | Historie abrufen (letzte 50) |
+| DELETE | `/api/history/:id` | Einzelnen Eintrag löschen |
+| DELETE | `/api/history` | Gesamte Historie löschen |
+
+## Weboberfläche
+
+Zweispaltiges Layout:
+- **Links:** Mail-Formular (Empfänger, CC, Betreff, Text/HTML-Toggle, Nachricht)
+- **Rechts:** Versand-Historie mit Status-Icons und Lösch-Buttons
+
+## Fehlerbehandlung
+
+| Fehlertyp | Behandlung |
+|-----------|------------|
+| Ungültige E-Mail-Adresse | Validierung Frontend + Backend |
+| SMTP-Verbindungsfehler | In DB als "failed" speichern |
+| Authentifizierungsfehler | Hinweis auf .env-Konfiguration |
+| Timeout | Nach 30 Sekunden Abbruch |
+| Leere Pflichtfelder | Frontend verhindert Absenden |
+
+## Konfiguration (.env)
+
+```env
+# Server
+PORT=3000
+
+# Email Configuration
+MAIL_PROVIDER=smtp
+MAIL_FROM_EMAIL=noreply@businesshelpdesk.biz
+MAIL_FROM_NAME=Secure Portal
+
+# SMTP (Brevo)
+SMTP_HOST=smtp-relay.brevo.com
+SMTP_PORT=587
+SMTP_USER=<user>
+SMTP_PASSWORD=<password>
+SMTP_SECURE=false
+```
+
+## Ausführung
+
+```bash
+npm install
+npm start
+```
+
+Server läuft auf http://localhost:3000
--- a/package-lock.json
+++ b/package-lock.json
--- a/package.json
+++ b/package.json
@@ -0,0 +1,19 @@
+{
+  "name": "mail-service",
+  "version": "1.0.0",
+  "description": "Web interface for testing email sending via Brevo SMTP",
+  "main": "src/server.js",
+  "scripts": {
+    "start": "node src/server.js",
+    "dev": "node --watch src/server.js"
+  },
+  "keywords": ["mail", "smtp", "brevo", "nodemailer"],
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "better-sqlite3": "^11.0.0",
+    "dotenv": "^16.4.0",
+    "express": "^4.18.0",
+    "nodemailer": "^6.9.0"
+  }
+}
--- a/public/index.html
+++ b/public/index.html
@@ -0,0 +1,65 @@
+<!DOCTYPE html>
+<html lang="de">
+<head>
+  <meta charset="UTF-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+  <title>Mail-Service</title>
+  <link rel="stylesheet" href="style.css">
+</head>
+<body>
+  <div class="container">
+    <div class="panel form-panel">
+      <h2>Mail Versenden</h2>
+      <form id="mailForm">
+        <div class="form-group">
+          <label for="to">Empfänger *</label>
+          <input type="email" id="to" name="to" required placeholder="empfaenger@example.com">
+        </div>
+
+        <div class="form-group">
+          <label for="cc">CC</label>
+          <input type="email" id="cc" name="cc" placeholder="cc@example.com">
+        </div>
+
+        <div class="form-group">
+          <label for="subject">Betreff *</label>
+          <input type="text" id="subject" name="subject" required placeholder="Betreff der E-Mail">
+        </div>
+
+        <div class="form-group">
+          <label>Format</label>
+          <div class="radio-group">
+            <label>
+              <input type="radio" name="format" value="text" checked> Text
+            </label>
+            <label>
+              <input type="radio" name="format" value="html"> HTML
+            </label>
+          </div>
+        </div>
+
+        <div class="form-group">
+          <label for="body">Nachricht *</label>
+          <textarea id="body" name="body" required rows="8" placeholder="Ihre Nachricht..."></textarea>
+        </div>
+
+        <button type="submit" id="submitBtn">Senden</button>
+      </form>
+
+      <div id="status" class="status hidden"></div>
+    </div>
+
+    <div class="panel history-panel">
+      <div class="history-header">
+        <h2>Versand-Historie</h2>
+        <button id="clearHistory" class="btn-secondary">Leeren</button>
+      </div>
+      <div id="historyList" class="history-list">
+        <p class="empty-message">Keine E-Mails gesendet</p>
+      </div>
+    </div>
+  </div>
+
+  <script src="script.js"></script>
+</body>
+</html>
--- a/public/script.js
+++ b/public/script.js
@@ -0,0 +1,149 @@
+document.addEventListener('DOMContentLoaded', () => {
+  const form = document.getElementById('mailForm');
+  const status = document.getElementById('status');
+  const submitBtn = document.getElementById('submitBtn');
+  const historyList = document.getElementById('historyList');
+  const clearHistoryBtn = document.getElementById('clearHistory');
+
+  // Load history on page load
+  loadHistory();
+
+  // Form submission
+  form.addEventListener('submit', async (e) => {
+    e.preventDefault();
+
+    const formData = new FormData(form);
+    const data = {
+      to: formData.get('to'),
+      cc: formData.get('cc') || undefined,
+      subject: formData.get('subject'),
+      body: formData.get('body'),
+      isHtml: formData.get('format') === 'html'
+    };
+
+    submitBtn.disabled = true;
+    submitBtn.textContent = 'Sende...';
+    hideStatus();
+
+    try {
+      const response = await fetch('/api/send', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(data)
+      });
+
+      const result = await response.json();
+
+      if (result.success) {
+        showStatus('E-Mail erfolgreich gesendet!', 'success');
+        form.reset();
+      } else {
+        showStatus(result.error, 'error');
+      }
+
+      loadHistory();
+    } catch (error) {
+      showStatus('Netzwerkfehler: ' + error.message, 'error');
+    } finally {
+      submitBtn.disabled = false;
+      submitBtn.textContent = 'Senden';
+    }
+  });
+
+  // Clear history
+  clearHistoryBtn.addEventListener('click', async () => {
+    if (!confirm('Gesamte Historie löschen?')) return;
+
+    try {
+      const response = await fetch('/api/history', { method: 'DELETE' });
+      const result = await response.json();
+
+      if (result.success) {
+        loadHistory();
+      }
+    } catch (error) {
+      console.error('Error clearing history:', error);
+    }
+  });
+
+  // Load history from server
+  async function loadHistory() {
+    try {
+      const response = await fetch('/api/history');
+      const result = await response.json();
+
+      if (result.success) {
+        renderHistory(result.history);
+      }
+    } catch (error) {
+      console.error('Error loading history:', error);
+    }
+  }
+
+  // Render history list
+  function renderHistory(history) {
+    if (!history || history.length === 0) {
+      historyList.innerHTML = '<p class="empty-message">Keine E-Mails gesendet</p>';
+      return;
+    }
+
+    historyList.innerHTML = history.map(item => `
+      <div class="history-item ${item.status}">
+        <div class="history-item-header">
+          <span class="history-item-status">
+            ${item.status === 'success' ? '✓ Erfolgreich' : '✗ Fehlgeschlagen'}
+          </span>
+          <button class="delete-btn" onclick="deleteHistoryItem(${item.id})" title="Löschen">✕</button>
+        </div>
+        <div class="history-item-date">${formatDate(item.created_at)}</div>
+        <div class="history-item-to">An: ${escapeHtml(item.to_email)}${item.cc_email ? `, CC: ${escapeHtml(item.cc_email)}` : ''}</div>
+        <div class="history-item-subject">Betreff: ${escapeHtml(item.subject)}</div>
+        ${item.error_message ? `<div class="history-item-error">Fehler: ${escapeHtml(item.error_message)}</div>` : ''}
+      </div>
+    `).join('');
+  }
+
+  // Delete single history item
+  window.deleteHistoryItem = async (id) => {
+    try {
+      const response = await fetch(`/api/history/${id}`, { method: 'DELETE' });
+      const result = await response.json();
+
+      if (result.success) {
+        loadHistory();
+      }
+    } catch (error) {
+      console.error('Error deleting item:', error);
+    }
+  };
+
+  // Show status message
+  function showStatus(message, type) {
+    status.textContent = message;
+    status.className = `status ${type}`;
+  }
+
+  // Hide status message
+  function hideStatus() {
+    status.className = 'status hidden';
+  }
+
+  // Format date
+  function formatDate(dateStr) {
+    const date = new Date(dateStr + 'Z');
+    return date.toLocaleString('de-DE', {
+      day: '2-digit',
+      month: '2-digit',
+      year: 'numeric',
+      hour: '2-digit',
+      minute: '2-digit'
+    });
+  }
+
+  // Escape HTML to prevent XSS
+  function escapeHtml(text) {
+    const div = document.createElement('div');
+    div.textContent = text;
+    return div.innerHTML;
+  }
+});
--- a/public/style.css
+++ b/public/style.css
@@ -0,0 +1,257 @@
+* {
+  box-sizing: border-box;
+  margin: 0;
+  padding: 0;
+}
+
+body {
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
+  background: #f5f5f5;
+  color: #333;
+  line-height: 1.6;
+}
+
+.container {
+  display: flex;
+  gap: 20px;
+  padding: 20px;
+  max-width: 1400px;
+  margin: 0 auto;
+  min-height: 100vh;
+}
+
+.panel {
+  background: white;
+  border-radius: 8px;
+  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
+  padding: 24px;
+}
+
+.form-panel {
+  flex: 1;
+  max-width: 600px;
+}
+
+.history-panel {
+  flex: 1;
+  max-width: 500px;
+}
+
+h2 {
+  margin-bottom: 20px;
+  color: #2c3e50;
+  font-size: 1.5rem;
+}
+
+.form-group {
+  margin-bottom: 16px;
+}
+
+label {
+  display: block;
+  margin-bottom: 6px;
+  font-weight: 500;
+  color: #555;
+}
+
+input[type="text"],
+input[type="email"],
+textarea {
+  width: 100%;
+  padding: 10px 12px;
+  border: 1px solid #ddd;
+  border-radius: 4px;
+  font-size: 14px;
+  transition: border-color 0.2s;
+}
+
+input:focus,
+textarea:focus {
+  outline: none;
+  border-color: #3498db;
+}
+
+textarea {
+  resize: vertical;
+  min-height: 150px;
+}
+
+.radio-group {
+  display: flex;
+  gap: 20px;
+}
+
+.radio-group label {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  font-weight: normal;
+  cursor: pointer;
+}
+
+button {
+  background: #3498db;
+  color: white;
+  border: none;
+  padding: 12px 24px;
+  border-radius: 4px;
+  font-size: 16px;
+  cursor: pointer;
+  transition: background 0.2s;
+}
+
+button:hover {
+  background: #2980b9;
+}
+
+button:disabled {
+  background: #bdc3c7;
+  cursor: not-allowed;
+}
+
+.btn-secondary {
+  background: #95a5a6;
+  padding: 8px 16px;
+  font-size: 14px;
+}
+
+.btn-secondary:hover {
+  background: #7f8c8d;
+}
+
+.status {
+  margin-top: 16px;
+  padding: 12px;
+  border-radius: 4px;
+  font-weight: 500;
+}
+
+.status.success {
+  background: #d4edda;
+  color: #155724;
+  border: 1px solid #c3e6cb;
+}
+
+.status.error {
+  background: #f8d7da;
+  color: #721c24;
+  border: 1px solid #f5c6cb;
+}
+
+.hidden {
+  display: none;
+}
+
+.history-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  margin-bottom: 16px;
+}
+
+.history-header h2 {
+  margin-bottom: 0;
+}
+
+.history-list {
+  max-height: calc(100vh - 180px);
+  overflow-y: auto;
+}
+
+.history-item {
+  padding: 12px;
+  border: 1px solid #eee;
+  border-radius: 4px;
+  margin-bottom: 10px;
+  position: relative;
+}
+
+.history-item.success {
+  border-left: 4px solid #27ae60;
+}
+
+.history-item.failed {
+  border-left: 4px solid #e74c3c;
+}
+
+.history-item-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: flex-start;
+  margin-bottom: 8px;
+}
+
+.history-item-status {
+  font-weight: 600;
+  font-size: 13px;
+}
+
+.history-item.success .history-item-status {
+  color: #27ae60;
+}
+
+.history-item.failed .history-item-status {
+  color: #e74c3c;
+}
+
+.history-item-date {
+  font-size: 12px;
+  color: #888;
+}
+
+.history-item-to {
+  font-size: 14px;
+  color: #333;
+  margin-bottom: 4px;
+}
+
+.history-item-subject {
+  font-size: 13px;
+  color: #666;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.history-item-error {
+  font-size: 12px;
+  color: #e74c3c;
+  margin-top: 6px;
+  word-break: break-word;
+}
+
+.delete-btn {
+  background: none;
+  border: none;
+  color: #bbb;
+  cursor: pointer;
+  padding: 4px 8px;
+  font-size: 16px;
+  transition: color 0.2s;
+}
+
+.delete-btn:hover {
+  color: #e74c3c;
+  background: none;
+}
+
+.empty-message {
+  text-align: center;
+  color: #999;
+  padding: 40px 20px;
+}
+
+@media (max-width: 900px) {
+  .container {
+    flex-direction: column;
+  }
+
+  .form-panel,
+  .history-panel {
+    max-width: 100%;
+  }
+
+  .history-list {
+    max-height: 400px;
+  }
+}
--- a/src/database.js
+++ b/src/database.js
@@ -0,0 +1,66 @@
+const Database = require('better-sqlite3');
+const path = require('path');
+
+const dbPath = path.join(__dirname, '..', 'data', 'emails.db');
+const db = new Database(dbPath);
+
+// Initialize database schema
+db.exec(`
+  CREATE TABLE IF NOT EXISTS emails (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    to_email TEXT NOT NULL,
+    cc_email TEXT,
+    subject TEXT NOT NULL,
+    body TEXT NOT NULL,
+    is_html INTEGER DEFAULT 0,
+    status TEXT NOT NULL,
+    error_message TEXT,
+    created_at TEXT DEFAULT (datetime('now'))
+  )
+`);
+
+const insertEmail = db.prepare(`
+  INSERT INTO emails (to_email, cc_email, subject, body, is_html, status, error_message)
+  VALUES (?, ?, ?, ?, ?, ?, ?)
+`);
+
+const getHistory = db.prepare(`
+  SELECT * FROM emails ORDER BY created_at DESC LIMIT 50
+`);
+
+const deleteEmail = db.prepare(`
+  DELETE FROM emails WHERE id = ?
+`);
+
+const deleteAllEmails = db.prepare(`
+  DELETE FROM emails
+`);
+
+module.exports = {
+  saveEmail(email, status, errorMessage = null) {
+    const result = insertEmail.run(
+      email.to,
+      email.cc || null,
+      email.subject,
+      email.body,
+      email.isHtml ? 1 : 0,
+      status,
+      errorMessage
+    );
+    return result.lastInsertRowid;
+  },
+
+  getHistory() {
+    return getHistory.all();
+  },
+
+  deleteEmail(id) {
+    const result = deleteEmail.run(id);
+    return result.changes > 0;
+  },
+
+  clearHistory() {
+    const result = deleteAllEmails.run();
+    return result.changes;
+  }
+};
--- a/src/mailer.js
+++ b/src/mailer.js
@@ -0,0 +1,84 @@
+const nodemailer = require('nodemailer');
+const path = require('path');
+
+const transporter = nodemailer.createTransport({
+  host: process.env.SMTP_HOST,
+  port: parseInt(process.env.SMTP_PORT, 10),
+  secure: process.env.SMTP_SECURE === 'true',
+  auth: {
+    user: process.env.SMTP_USER,
+    pass: process.env.SMTP_PASSWORD
+  },
+  connectionTimeout: 30000,
+  greetingTimeout: 30000,
+  socketTimeout: 30000
+});
+
+const FOOTER_NAME = process.env.MAIL_FOOTER_NAME || 'Joachim Hummel';
+const FOOTER_IMAGE = path.join(__dirname, '..', 'assets', 'homeicon.png');
+
+function getHtmlFooter() {
+  return `
+    <br/><br/>
+    <hr style="border: none; border-top: 1px solid #ddd; margin: 20px 0;"/>
+    <table cellpadding="0" cellspacing="0" style="font-family: Arial, sans-serif; font-size: 14px; color: #666;">
+      <tr>
+        <td style="vertical-align: middle; padding-right: 10px;">
+          <img src="cid:homeicon" alt="Home" width="40" height="40" style="display: block;"/>
+        </td>
+        <td style="vertical-align: middle;">
+          <strong>Absender</strong><br/>
+          ${FOOTER_NAME}
+        </td>
+      </tr>
+    </table>
+  `;
+}
+
+function getTextFooter() {
+  return `\n\n---\nAbsender - ${FOOTER_NAME}`;
+}
+
+async function sendMail(email) {
+  const mailOptions = {
+    from: `"${process.env.MAIL_FROM_NAME}" <${process.env.MAIL_FROM_EMAIL}>`,
+    to: email.to,
+    subject: email.subject,
+    attachments: [
+      {
+        filename: 'homeicon.png',
+        path: FOOTER_IMAGE,
+        cid: 'homeicon'
+      }
+    ]
+  };
+
+  if (email.cc) {
+    mailOptions.cc = email.cc;
+  }
+
+  if (email.isHtml) {
+    mailOptions.html = email.body + getHtmlFooter();
+  } else {
+    mailOptions.text = email.body + getTextFooter();
+    // Also send HTML version with footer for better display
+    mailOptions.html = `<pre style="font-family: inherit; white-space: pre-wrap;">${email.body}</pre>` + getHtmlFooter();
+  }
+
+  const info = await transporter.sendMail(mailOptions);
+  return info;
+}
+
+async function verifyConnection() {
+  try {
+    await transporter.verify();
+    return { success: true };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+module.exports = {
+  sendMail,
+  verifyConnection
+};
--- a/src/server.js
+++ b/src/server.js
@@ -0,0 +1,126 @@
+require('dotenv').config();
+
+const express = require('express');
+const path = require('path');
+const db = require('./database');
+const mailer = require('./mailer');
+
+const app = express();
+const PORT = process.env.PORT || 3000;
+
+// Middleware
+app.use(express.json());
+app.use(express.static(path.join(__dirname, '..', 'public')));
+
+// Email validation helper
+function isValidEmail(email) {
+  const re = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
+  return re.test(email);
+}
+
+// API Routes
+
+// Send email
+app.post('/api/send', async (req, res) => {
+  const { to, cc, subject, body, isHtml } = req.body;
+
+  // Validation
+  if (!to || !subject || !body) {
+    return res.status(400).json({
+      success: false,
+      error: 'Empfänger, Betreff und Nachricht sind Pflichtfelder'
+    });
+  }
+
+  if (!isValidEmail(to)) {
+    return res.status(400).json({
+      success: false,
+      error: 'Ungültige Empfänger-E-Mail-Adresse'
+    });
+  }
+
+  if (cc && !isValidEmail(cc)) {
+    return res.status(400).json({
+      success: false,
+      error: 'Ungültige CC-E-Mail-Adresse'
+    });
+  }
+
+  const email = { to, cc, subject, body, isHtml: !!isHtml };
+
+  try {
+    const info = await mailer.sendMail(email);
+    const id = db.saveEmail(email, 'success');
+    console.log(`Email sent successfully: ${info.messageId}`);
+
+    res.json({
+      success: true,
+      message: 'E-Mail erfolgreich gesendet',
+      messageId: info.messageId,
+      id
+    });
+  } catch (error) {
+    console.error('Email sending failed:', error.message);
+    const id = db.saveEmail(email, 'failed', error.message);
+
+    res.status(500).json({
+      success: false,
+      error: `Versand fehlgeschlagen: ${error.message}`,
+      id
+    });
+  }
+});
+
+// Get history
+app.get('/api/history', (req, res) => {
+  try {
+    const history = db.getHistory();
+    res.json({ success: true, history });
+  } catch (error) {
+    res.status(500).json({ success: false, error: error.message });
+  }
+});
+
+// Delete single entry
+app.delete('/api/history/:id', (req, res) => {
+  const id = parseInt(req.params.id, 10);
+
+  if (isNaN(id)) {
+    return res.status(400).json({ success: false, error: 'Ungültige ID' });
+  }
+
+  try {
+    const deleted = db.deleteEmail(id);
+    if (deleted) {
+      res.json({ success: true, message: 'Eintrag gelöscht' });
+    } else {
+      res.status(404).json({ success: false, error: 'Eintrag nicht gefunden' });
+    }
+  } catch (error) {
+    res.status(500).json({ success: false, error: error.message });
+  }
+});
+
+// Clear all history
+app.delete('/api/history', (req, res) => {
+  try {
+    const count = db.clearHistory();
+    res.json({ success: true, message: `${count} Einträge gelöscht` });
+  } catch (error) {
+    res.status(500).json({ success: false, error: error.message });
+  }
+});
+
+// Start server
+app.listen(PORT, () => {
+  console.log(`Mail-Service läuft auf http://localhost:${PORT}`);
+
+  // Verify SMTP connection on startup
+  mailer.verifyConnection().then(result => {
+    if (result.success) {
+      console.log('SMTP-Verbindung erfolgreich verifiziert');
+    } else {
+      console.warn('SMTP-Verbindung konnte nicht verifiziert werden:', result.error);
+    }
+  });
+});