Spacebar Studio

Deliverability problems often develop gradually, then seem to appear suddenly. Regular audits catch issues before they become crises. This newsletter deliverability checklist gives you a systematic way to evaluate and improve your email deliverability.

Use this checklist quarterly for maintenance, or immediately when you notice deliverability issues. Each item includes why it matters and how to verify it’s correctly configured.

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Authentication Checklist

Authentication proves you’re authorized to send emails from your domain.

SPF Configuration

☐ SPF record exists
Check DNS for a TXT record starting with v=spf1

☐ Includes your email platform
Record includes your platform’s sending servers

☐ Not exceeding lookup limits
SPF allows a maximum of 10 DNS lookups

☐ Ends correctly
Ends with ~all or -all

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How to verify

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Use tools like MXToolbox or your email platform’s verification feature. Send a test email and check headers for an SPF pass.

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Why it matters

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Without SPF, receiving servers can’t verify that you authorized the sending server, increasing the chance your emails are marked as spam.

DKIM Configuration

☐ DKIM enabled
Enabled in your email platform settings

☐ DNS record exists
Public key published in your domain’s DNS

☐ Signature working
Test emails show DKIM pass in headers

☐ Correct selector used
Matches your platform’s requirements

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How to verify

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Send a test email and check headers for dkim=pass in authentication results.

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Why it matters

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DKIM confirms message integrity and sender authenticity.

DMARC Configuration

☐ DMARC record exists
TXT record at _dmarc.yourdomain.com

☐ Policy defined
p=none, p=quarantine, or p=reject

☐ Reporting configured
Includes rua= tag for reports

☐ Alignment working
SPF and DKIM are passing and aligned

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How to verify

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Check DNS and review DMARC aggregate reports.

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‍Why it matters

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DMARC tells inbox providers how to handle failed authentication and gives visibility into who’s sending from your domain.

Custom Sending Domain

☐ Custom domain configured
Not using a platform default domain

☐ All records verified
Platform shows verified status

☐ Consistent usage
All emails sent from the custom domain

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Why it matters

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Custom domains build your own sender reputation and increase trust.

List Quality Checklist

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Clean lists are essential for good deliverability.

Signup Process

☐ Double opt-in enabled
Subscribers confirm via email

☐ Clear expectations set
Subscribers know what they’re signing up for

☐ Relevant lead magnets
Attract the right audience

☐ No pre-checked boxes
Explicit consent required

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Why it matters

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High-quality signups lead to higher engagement and fewer spam complaints.

Bounce Management

☐ Hard bounces removed
Automatically removed after first occurrence

☐ Soft bounces monitored
Removed after repeated failures

☐ Bounce rate acceptable
Under 2% per send

☐ Bounce reasons reviewed
Patterns analyzed

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How to check

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Review bounce reports in your email platform.

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Why it matters

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High bounce rates damage sender reputation.

Inactive Subscriber Management

☐ Inactive defined
Example: no opens in 90 days

☐ Re-engagement campaign sent

☐ Non-responders removed

☐ Regular cleaning scheduled
Monthly or quarterly

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Why it matters

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Inactive subscribers reduce engagement and may include abandoned inboxes.

Spam Trap Avoidance

☐ No purchased lists

☐ No scraped emails

☐ Regular validation

☐ Clean import practices

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Why it matters

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Spam traps can severely harm deliverability and are common in old or purchased lists.

Content Checklist

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What you send affects inbox placement.

Email Structure

☐ Plain text version included
☐ Healthy text-to-image ratio
☐ Clean HTML
☐ Mobile-friendly rendering
☐ Email size under 100 KB

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Why it matters

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Well-structured emails are easier for inbox providers to trust.

Subject Lines

☐ Avoid spam triggers
☐ Honest and relevant
☐ Under 50 characters
☐ No deceptive tactics

Body Content

☐ Physical mailing address included
☐ Visible unsubscribe link
☐ No URL shorteners
☐ All links functional
☐ Consistent sender name

Testing Before Send

☐ Test email sent
☐ Checked in multiple inboxes
☐ Spam score reviewed
☐ Links verified

Reputation Checklist

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Monitor your sender reputation.

Google Postmaster Tools

☐ Account set up
☐ Domain verified
☐ Reviewed weekly or monthly
☐ No high-severity issues

Microsoft SNDS

☐ Account created
☐ Sending IPs registered
☐ Status monitored regularly

Platform Monitoring

☐ Bounce rates reviewed
☐ Complaint rates under 0.1%
☐ Open rate trends monitored
☐ Platform warnings addressed

Blacklist Checking

☐ IP not blacklisted
☐ Domain not blacklisted
☐ Monthly monitoring in place

Engagement Checklist

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Engagement strongly influences inbox placement.

Open Rate Health

☐ Baseline established
☐ Trends monitored
☐ Segment performance compared
☐ Subject lines tested

Benchmark
B2B newsletters: 30%+ open rate

Click Rate Health

☐ Baseline established
☐ Clear CTAs
☐ Valuable links
☐ Easy-to-scan formatting

Benchmark
B2B newsletters: 3%+ click rate

Complaint Rate

☐ Below 0.1%
☐ Feedback reviewed
☐ Root causes addressed

Unsubscribe Rate

☐ Between 0.5–2%
☐ One-click unsubscribe
☐ Optional exit feedback

Platform and Infrastructure Checklist

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Email Platform Health

☐ Account in good standing
☐ Sending limits respected
☐ Deliverability features enabled
☐ Integrations working

Sending Patterns

☐ Consistent schedule
☐ No sudden volume spikes
☐ Proper warmup for new domains/IPs

Compliance

☐ CAN-SPAM compliant
☐ GDPR compliant (if applicable)
☐ Unsubscribes honored promptly

Red Flags Requiring Immediate Action

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1. Authentication failures
2. Bounce rate above 5%
3. Complaint rate above 0.3%
4. Blacklisting detected
5. 30%+ open rate drop
6. ESP warnings or restrictions

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