{
  "type": "email.bounced",
  "data": {
    "emailId": "email_123",
    "to": "invalid@nonexistent.com",
    "bounceType": "hard",
    "bounceCategory": "invalid_address",
    "message": "550 5.1.1 The email account does not exist"
  }
}

{
  "type": "email.bounced",
  "data": {
    "emailId": "email_456",
    "to": "full@example.com",
    "bounceType": "soft",
    "bounceCategory": "mailbox_full",
    "message": "452 4.2.2 Mailbox full"
  }
}

// Webhook handler
app.post('/webhooks/lettr', (req, res) => {
  const event = req.body;
  
  if (event.type === 'email.bounced') {
    const { to, bounceType, bounceCategory } = event.data;
    
    if (bounceType === 'hard') {
      // Remove from your mailing list
      await removeFromMailingList(to);
      
      // Notify the user if needed
      await notifyUser(to, bounceCategory);
    }
  }
  
  res.sendStatus(200);
});

// List all bounces
const bounces = await lettr.bounces.list({
  startDate: '2024-01-01',
  endDate: '2024-01-31'
});

// Get bounce rate statistics
const stats = await lettr.stats.get({
  startDate: '2024-01-01',
  endDate: '2024-01-31'
});

console.log(`Bounce rate: ${stats.bounceRate}%`);