Email Deliverability

What Is Deliverability?

Deliverability is the ability to reach recipients’ inboxes. Poor deliverability means emails go to spam or get blocked entirely.

Key Factors

Sender Reputation

Your reputation is based on:

• Bounce rates
• Spam complaints
• Engagement (opens, clicks)
• Sending patterns

Authentication

Email authentication proves you’re allowed to send from your domain:

• SPF - Lists authorized sending servers
• DKIM - Cryptographically signs messages
• DMARC - Tells receivers how to handle failures

Content

What you send matters:

• Spam trigger words
• Image-to-text ratio
• Link quality

Setting Up Authentication

SPF (Sender Policy Framework)

Add a TXT record to your domain’s DNS:

v=spf1 include:_spf.yourprovider.com ~all

Replace _spf.yourprovider.com with your email provider’s SPF domain.

DKIM (DomainKeys Identified Mail)

Add the DKIM record your provider gives you:

Type: CNAME or TXT
Name: selector._domainkey.yourdomain.com
Value: (provided by your email provider)

DMARC

Add a DMARC policy:

v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com

Start with p=none to monitor, then move to p=quarantine or p=reject.

Provider-Specific Setup

Resend

1. Go to Domains
2. Add your domain
3. Add provided DNS records
4. Wait for verification

SendGrid

1. Go to Sender Authentication
2. Authenticate your domain
3. Add DNS records
4. Verify

Postmark

1. Go to Sender Signatures
2. Add domain
3. Configure DNS
4. Verify

AWS SES

1. Go to Verified Identities
2. Add domain
3. Configure DKIM
4. Verify ownership

Common Deliverability Issues

Going to Spam

Causes:

• Missing authentication (SPF, DKIM, DMARC)
• Spammy content
• Poor sender reputation
• Recipient marked previous email as spam

Solutions:

1. Set up all authentication records
2. Review content for spam triggers
3. Check sender reputation
4. Remove recipients who marked you as spam

Being Blocked

Causes:

• Blacklisted IP or domain
• High bounce rate
• Sending to spam traps

Solutions:

1. Check blacklists (MXToolbox, etc.)
2. Clean your email list
3. Use double opt-in for new subscribers
4. Contact the blocking party for removal

Low Open Rates

Causes:

• Poor subject lines
• Landing in spam
• Wrong audience
• Bad sending time

Solutions:

1. A/B test subject lines
2. Check spam placement
3. Segment your audience
4. Test different send times

Content Best Practices

Avoid Spam Triggers

Don’t use:

• ALL CAPS
• Excessive punctuation!!!
• Spam words (free, act now, limited time)
• Deceptive subject lines

Image-to-Text Ratio

• Don’t send image-only emails
• Include meaningful text content
• Aim for more text than images

Links

• Use your own domain for links
• Don’t use URL shorteners (they get flagged)
• Limit number of links

Monitoring Deliverability

Provider Dashboards

Check your email provider’s analytics:

• Delivery rate
• Bounce rate
• Spam complaints
• Opens and clicks

Warning Signs

Act immediately if you see:

• Bounce rate > 5%
• Spam complaints > 0.1%
• Sudden drop in open rates
• Delivery failures

Warming Up New Domains/IPs

New sending domains need warming:

1. Start small - Send few emails initially
2. Increase gradually - Double volume weekly
3. Target engaged users - Send to people who will open
4. Monitor closely - Watch for deliverability issues

Example schedule:

• Week 1: 50 emails/day
• Week 2: 100 emails/day
• Week 3: 200 emails/day
• Continue doubling until target volume

Testing Deliverability

Tools

• Mail Tester (mail-tester.com) - Score your emails
• MXToolbox - Check DNS and blacklists
• GlockApps - Inbox placement testing

Process

1. Send test email to testing service
2. Review score and issues
3. Fix identified problems
4. Retest until score improves