Email Deliverability Best Practices

Want your emails to actually reach inboxes instead of spam folders? Here’s everything you need to know about email deliverability.

🏠 Domain & DNS Setup

SPF Record

SPF lists the servers allowed to send for your domain. The record comes from your email provider. For Amazon SES with a custom MAIL FROM domain, it is:

v=spf1 include:amazonses.com ~all

See Send with Amazon SES for the full setup.

DKIM Authentication

DKIM signs each message so receivers can check it was not altered. Most providers generate the keys for you: in Amazon SES, Easy DKIM gives you three CNAME records to add to your DNS. Turn DKIM on with your provider rather than creating keys by hand.

DMARC Policy

Set up DMARC to monitor and protect your domain:

v=DMARC1; p=quarantine; rua=mailto:dmarc@yourdomain.com

📧 Email Content Best Practices

Subject Lines

✅ Do:

Keep under 50 characters
Be specific and relevant
Use personalization: “Hey , your order is ready!”
Test different variations

❌ Don’t:

Use ALL CAPS
Include spam trigger words: “FREE”, “ACT NOW”, “LIMITED TIME”
Use excessive punctuation: ”!!!”
Be misleading or clickbait

Email Body

✅ Do:

Use a clear, professional tone
Include your physical address (required by law)
Provide an unsubscribe link
Test on mobile devices
Keep HTML simple and clean

❌ Don’t:

Use excessive images (text-to-image ratio should be 80:20)
Include suspicious links
Use poor grammar or spelling
Send from “noreply@” addresses

📊 List Management

Clean Your List Regularly

// Remove bounced emails
const cleanList = async (emailList) => {
  const cleaned = emailList.filter(email => {
    return !email.bounced && !email.unsubscribed;
  });
  return cleaned;
};

Double Opt-in

Always confirm subscriptions:

// Send confirmation email
await sendEmail({
  to: user.email,
  subject: "Confirm your subscription",
  body: `Click here to confirm: ${confirmationLink}`
});

Unsubscribe Handling

Make it easy to unsubscribe:

<!-- Always include this -->
<p>Don't want these emails? <a href="{{unsubscribe_url}}">Unsubscribe</a></p>

🚀 Sending Best Practices

Warm Up Your IP

Start slow and gradually increase volume:

Day 1-7: 50 emails/day
Day 8-14: 100 emails/day
Day 15-21: 250 emails/day
Day 22+: 500+ emails/day

Send at Optimal Times

Based on your audience:

B2B: Tuesday-Thursday, 9-11 AM
B2C: Tuesday-Thursday, 6-8 PM
Weekends: Avoid unless your audience is active

Monitor Your Reputation

Track these metrics:

Bounce Rate: Keep under 2%
Spam Complaints: Keep under 0.1%
Open Rate: Aim for 20%+
Click Rate: Aim for 2%+

🔧 Technical Setup

SMTP Configuration

// Use proper SMTP settings
const smtpConfig = {
  host: 'smtp.gmail.com',
  port: 587,
  secure: false, // Use TLS
  auth: {
    user: 'your-email@gmail.com',
    pass: 'your-app-password'
  }
};

Rate Limiting

Respect rate limits to avoid being flagged:

// Implement exponential backoff
const sendWithBackoff = async (email, retries = 3) => {
  try {
    return await sendEmail(email);
  } catch (error) {
    if (error.status === 429 && retries > 0) {
      await new Promise(resolve => 
        setTimeout(resolve, Math.pow(2, 4 - retries) * 1000)
      );
      return sendWithBackoff(email, retries - 1);
    }
    throw error;
  }
};

📈 Monitoring & Testing

Test Before Sending

// Send test emails to yourself first
const testEmail = async () => {
  await sendEmail({
    to: 'your-email@domain.com',
    subject: 'Test Email',
    body: 'This is a test email'
  });
};

Monitor Deliverability

Check these regularly:

Inbox Placement: Use tools like Mail Tester
Spam Score: Keep under 5/10
Authentication: Verify SPF, DKIM, DMARC
Blacklist Status: Check major blacklists

🛠️ Tools & Resources

Testing Tools

Mail Tester: Test email deliverability
GlockApps: Check spam score
250ok: Monitor sending reputation
MXToolbox: Check blacklist status

Monitoring Services

Postmark: Real-time delivery tracking
SendGrid: Detailed analytics
Mailgun: Bounce and complaint handling

🚨 Common Mistakes to Avoid

Buying Email Lists: Never buy lists - always grow organically
Ignoring Bounces: Remove hard bounces immediately
Sending Too Fast: Respect rate limits and warm up gradually
Poor List Hygiene: Clean your list regularly
No Authentication: Always set up SPF, DKIM, DMARC

📞 Need Help?

If you’re still having deliverability issues:

Check your sending reputation on major ISPs
Review your email content for spam triggers
Verify your DNS settings are correct
Contact our support team for personalized help

Support: team@xem.email Community: Discord

Overview

Troubleshooting

Best Practices

Performance

Email deliverability