Email Deliverability

Technical checks to ensure email deliverability and authentication

Version 1.0.0Updated Jan 21, 2025
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Checks

SPF Record Configured

Verify SPF (Sender Policy Framework) record exists and is valid

SPF prevents email spoofing and improves deliverability

critical

DKIM Signature

Verify DKIM (DomainKeys Identified Mail) is configured and signing emails

DKIM provides email authentication and improves deliverability

critical

DMARC Policy

Verify DMARC (Domain-based Message Authentication) policy is configured

DMARC protects against email spoofing and phishing

critical

Reverse DNS (PTR) Record

Verify reverse DNS record exists for sending IP

Reverse DNS improves sender reputation

major

Bounce Handling

Verify bounce handling is configured (return-path, bounce address)

Proper bounce handling prevents blacklisting

critical

List-Unsubscribe Header

Verify List-Unsubscribe header is present in emails

Required by Gmail and improves deliverability

major

From Address Consistency

Verify From address domain matches sending domain

Domain mismatch triggers spam filters

major

Reply-To Address

Verify Reply-To address is set and valid

Proper reply handling improves engagement

minor

IP Reputation Check

Verify sending IP is not on blacklists

Blacklisted IPs have poor deliverability

critical

Domain Reputation Check

Verify sending domain is not on blacklists

Blacklisted domains have poor deliverability

critical

SPF -all Mechanism

Verify SPF record ends with -all or ~all (not +all)

Strict SPF policy prevents unauthorized sending

major

DMARC Policy Enforcement

Verify DMARC policy is set to quarantine or reject (not none)

Enforcement protects against spoofing

major

DKIM Key Length

Verify DKIM key is at least 1024 bits

Shorter keys are less secure

major

MX Records Configured

Verify MX records exist for domain

Required for receiving email

critical

TXT Records Valid

Verify all TXT records (SPF, DMARC) are valid and not too long

Invalid or overly long records cause issues

major

Sending Rate Limits

Verify sending rate is within provider limits

Exceeding limits causes throttling

major

IP Warmup Process

Verify new IPs follow warmup process

Gradual warmup improves reputation

recommended

Engagement Tracking

Verify opens and clicks are being tracked

Engagement metrics improve deliverability

recommended

Unsubscribe Link

Verify unsubscribe link is present and functional

Required by law (CAN-SPAM, GDPR) and improves deliverability

critical

Physical Address

Verify physical mailing address is included (CAN-SPAM requirement)

Required by CAN-SPAM Act

critical

Subject Line Length

Verify subject line is under 50 characters (mobile-friendly)

Long subject lines get truncated

minor

Preheader Text

Verify preheader text is present and meaningful

Preheader improves open rates

recommended

Image Alt Text

Verify all images have alt text

Alt text improves accessibility and deliverability

major

HTML Validation

Verify HTML is valid and well-formed

Invalid HTML can cause rendering issues

major