The 2025 Email Deliverability Checklist: 47 Things to Check Before You Send

The Pre-Send Deliverability Checklist

Before you hit send on any email campaign, run through this list. Bookmark this page — it's designed to be your go-to reference for every send.

🔐 Authentication (Must-Have)

1. SPF record is published and includes all sending sources
2. SPF includes your ESP's servers (SendGrid, Mailchimp, etc.)
3. SPF record has fewer than 10 DNS lookups (avoid too many include: chains)
4. DKIM is configured with a key length of 2048 bits or higher
5. DKIM selector is correct for your ESP
6. DMARC record exists (at minimum p=none with a rua= reporting address)
7. DMARC policy is set to p=quarantine or p=reject for maximum protection
8. BIMI record is set up (optional, but improves brand visibility in Gmail)

🏥 Domain Health

1. Domain is not on any major blacklists (check 120+ lists)
2. Sending IP is not on any major IP blacklists
3. Reverse DNS (rDNS/PTR) resolves correctly for your sending IP
4. MX records are configured and valid
5. TLS 1.2 or 1.3 is supported by your sending server
6. Domain is at least 30 days old (ideally 90+ days for new domains)
7. Domain has a valid, live website at the root (not a parked page)

📋 List Hygiene

1. All contacts opted in explicitly (single or double opt-in)
2. List has been cleaned of invalid emails (use email verification)
3. Hard bounces from previous sends have been removed
4. Unsubscribers from all previous sends have been suppressed
5. Contacts who haven't engaged in 6+ months are segmented separately
6. No purchased, scraped, or rented lists are included
7. You have not imported any lists from a third party without consent verification

✍️ Content

1. Subject line is under 60 characters
2. Subject line doesn't use all-caps or excessive punctuation (!!!, ???)
3. Subject line doesn't contain classic spam words ("free," "guaranteed," "act now")
4. Preheader text is set (not blank — blank preheader wastes valuable attention)
5. From name is recognizable and consistent with your brand
6. From address uses your verified domain (not Gmail, Yahoo, etc.)
7. Reply-to address is monitored by a real person
8. Email contains at least 200 words of real text (not image-only)
9. Image-to-text ratio is balanced (not more than 60% images)
10. All images have alt text
11. Number of links is reasonable (3–7 for marketing, 1–2 for sales)
12. All links are live and return a 200 status code
13. Unsubscribe link is present and working
14. Physical mailing address is included in the footer (CAN-SPAM requirement)
15. Email renders correctly in Dark Mode

📨 Technical

1. HTML is valid and doesn't contain broken tags
2. Email is under 100KB in size (Gmail clips larger emails)
3. The List-Unsubscribe header is set (enables one-click unsubscribe in Gmail/Outlook)
4. The List-Unsubscribe-Post header is set for RFC 8058 compliance
5. Email was tested in major clients: Gmail, Outlook, Apple Mail, Yahoo
6. Mobile rendering was verified (60%+ of email opens are on mobile)
7. Links contain UTM parameters for analytics tracking
8. Tracking domain is set up on your own subdomain (not ESP's default)

⚡ Sending Practices

1. Volume increase is less than 20% from your previous send (avoid sudden spikes)
2. Send time is optimized for your audience's timezone and behavior patterns

✅ Final Checks

Run a test send to yourself at Gmail, Outlook, and Yahoo. Check:

• Does it land in the inbox (not spam)?
• Does the subject, from name, and preheader look correct?
• Do all links work?
• Does it look good on mobile?

Only when all boxes are checked should you hit send to your full list.

Use Email In Inbox's AI Content Analyzer to automate checks 23–37 in seconds.