Amazon SES Email Deliverability Best Practices Avoiding Spam Folders

Amazon SES Email Deliverability Best Practices

Even with SES configured correctly, your emails might end up in spam. This guide covers how to maximize deliverability.

1. Complete DNS Authentication

SPF (Sender Policy Framework):

Type: TXT
Name: @
Value: v=spf1 include:amazonses.com ~all

DKIM (DomainKeys Identified Mail): Add the 3 CNAME records that SES provides. This adds a digital signature to each email.

DMARC:

Type: TXT
Name: _dmarc
Value: v=DMARC1; p=quarantine; rua=mailto:[email protected]

Without these three, most email providers will send your emails to spam.

2. Warm Up Your Domain

Don't send 10,000 emails on day one. Start small and increase gradually:

• Week 1: 50 emails/day
• Week 2: 200 emails/day
• Week 3: 500 emails/day
• Week 4: 1,000 emails/day
• Week 5+: Continue increasing

This builds sender reputation gradually. Sudden spikes trigger spam filters.

3. Handle Bounces and Complaints

// Set up SNS notification for bounces
// SES → Configuration Sets → Event Publishing → SNS

// When you get a bounce notification:
const handleBounce = async (email) => {
  await User.findOneAndUpdate(
    { email },
    { 
      emailBounced: true, 
      emailBouncedAt: new Date(),
      // Never send to this email again
    }
  );
};

// When you get a complaint (user marked as spam):
const handleComplaint = async (email) => {
  await User.findOneAndUpdate(
    { email },
    { 
      emailComplained: true,
      emailComplainedAt: new Date(),
      // Never send to this email again
    }
  );
};

// Before sending, check:
const canSendEmail = (user) => {
  return !user.emailBounced && !user.emailComplained;
};

Bounce rate should be < 5%. Complaint rate should be < 0.1%.

4. Use a Consistent From Address

// Good: consistent from address
from: "DevTinder <[email protected]>"

// Bad: changing from addresses
from: "[email protected]"  // one day
from: "[email protected]"  // another day

Consistent from addresses build sender reputation. Use sub-addresses for different purposes:

• [email protected] Transactional (no replies expected)
• [email protected] Support
• [email protected] Marketing

5. Clean Email Content

Do:

• Personalize the email (use the recipient's name)
• Keep a good text-to-HTML ratio
• Use clear, descriptive subject lines
• Include a plain text version
• Use a reputable domain

Don't:

• Use ALL CAPS in subject lines
• Use spam trigger words (FREE, GUARANTEE, ACT NOW)
• Use red text on white background
• Include too many images
• Use tiny font sizes
• Include attachments (link instead)

6. Include Unsubscribe Links

For notification emails (not pure transactional):

<p style="font-size:12px;color:#999;">
  You're receiving this because you have a DevTinder account.
  <a href="https://app.yourdomain.com/settings/notifications">Manage notification preferences</a>
</p>

7. Monitor with SES Metrics

SES provides dashboards for:

• Send volume Emails sent per day
• Bounce rate Percentage of bounced emails
• Complaint rate Percentage of spam complaints
• Delivery rate Percentage successfully delivered
• Open rate Percentage opened (with tracking)
• Click rate Percentage of links clicked

Set up CloudWatch alarms for high bounce or complaint rates.

8. Use Dedicated IPs for High Volume

SES shared IPs are fine for most apps. For very high volume (>100k/month), consider a dedicated IP:

• Dedicated IP $24.95/month per IP
• Better control over sender reputation
• No impact from other SES users

9. Test Before Sending

# Use mail-tester.com
# Send an email to the address they give you
# Get a score out of 10
# Aim for 9-10

# Also test with:
# GlockApps   Spam filter testing across providers
# SenderScore   Check your IP reputation

The Takeaway

Email deliverability requires: complete DNS authentication (SPF, DKIM, DMARC), warming up your domain gradually, handling bounces and complaints (never send to bounced/complained addresses), using a consistent from address, clean email content (no spam triggers), unsubscribe links for notifications, monitoring SES metrics, and testing with mail-tester.com before sending to users.