9 Email Deliverability Checklist for 2025 (Fix Before Sending!)

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If Your Emails Aren’t Landing, You’re Losing Opportunities

You put in the effort—crafting the perfect email, personalizing every detail, and hitting “send.” But then… nothing.

No replies. Low open rates. And the worst part? You don’t even know if your emails are reaching real inboxes or getting trapped in spam filters.

Email deliverability isn’t just another metric—it’s the make-or-break factor for cold email success. You can have the best offer in the world, but if your emails aren’t being delivered (or worse, flagged as spam), none of it matters.

Most people don’t even realize they have a deliverability problem until it’s too late.

So, let’s fix that.

This Email Deliverability Checklist is your step-by-step guide to ensuring every email you send has the highest chance of landing in the inbox. We’re skipping the fluff and getting straight into:

  • What Affects Email Deliverability?
  • Email Deliverability Checklist
  • Things to Do First If You’re Already in Spam

Plus, you’ll get a free downloadable checklist so you can quickly check your email deliverability before every campaign.

What Affects Email Deliverability?

Email deliverability depends on a few key factors that work together to help your emails reach the inbox. Let’s break them down:

1. Technical Factors:

  • DNS Records: Make sure you have SPF, DKIM, and DMARC set up correctly. These records confirm your identity to email providers.
  • IP and Domain: Using a dedicated IP and having a good domain reputation helps prevent your emails from being marked as spam.

2. Sender Behavior & Reputation:

  • Sending Habits: How often you send emails, how many bounce back, and the rate of spam complaints all affect your reputation.
  • Consistency: Sending emails steadily and avoiding sudden spikes can keep your reputation intact.

3. Email Content & Structure:

  • Content Quality: Avoid using too many images, spam trigger words, or overly salesy language.
  • Formatting: Keeping your emails clear and easy to read increases the chance they will pass through spam filters.

Also Read:

4. Subscriber Engagement:

  • Interaction: High open and click rates signal to email providers that your emails are wanted.
  • List Maintenance: Regularly remove inactive or invalid email addresses to maintain a healthy list.

By paying attention to these factors, you can improve your email deliverability and ensure your messages land in the inbox.

Email Deliverability Checklist for 2025 (Do This Before You Hit Send!)

1. Fix Your Technical Setup (Do This First!)

  • Set Up SPF, DKIM, and DMARC:
    Confirm these records are correctly configured to prove your identity to email providers.
  • Verify Your Configuration:
    Use tools like Google’s Postmaster Tools or MXToolbox to double-check your setup.
  • Custom Tracking Domain:
    Instead of using default domains, set up a custom tracking domain.
  • Enable Reverse DNS (rDNS):
    Make sure your IP address matches your domain.
  • Use a Reputable Email Service:
    Rely on trusted providers like Google Workspace, Outlook, or a robust SMTP API.

2. Check & Improve Your Email Reputation

  • Monitor Your Sender Score:
    Keep tabs using Google Postmaster, Talos, or Barracuda.
  • Blacklist Check:
    Regularly verify your domain and IP against blacklists using MxToolbox or Spamhaus.
  • Maintain Low Complaint Rates:
    Aim for spam complaints under 0.1% and bounce rates below 2%.
  • Use a Dedicated Domain:
    For cold outreach, stick to a dedicated domain instead of a generic one.

3. Clean & Verify Your Email List Before Sending

  • Purge Problem Addresses:
    Remove invalid, inactive, and spam-trap emails.
  • Email Verification Tools:
    Tools like Sparkle Email Verifier, NeverBounce, and ZeroBounce can help.
  • Regular List Maintenance:
    Clean your list at least once a month.
  • Segment Your Audience:
    Tailor your messaging by grouping contacts, instead of blasting one message to everyone.
  • Manage Bounces:
    Remove hard bounces immediately and monitor soft bounces carefully.

4. Warm Up Your Email Properly

  • Use Automated Warm-Up Tools:
    Tools like Lemwarm, Mailreach, Instantly, or Warmbox can simulate real engagement.
  • Start Gradually:
    Increase your sending volume slowly over 30 days.
  • Mimic Human Engagement:
    Encourage opens, clicks, and replies as part of your warm-up routine.
  • Monitor Performance:
    Keep an eye on open rates and spam flags during this period.

5. Optimize Your Email Sending Strategy

  • Control Your Volume:
    Limit cold emails to 50–100 per inbox per day.
  • Multiple Domains & Mailboxes:
    Use these to safely scale your outreach.
  • Rotate Email Addresses:
    Prevent domain fatigue by switching addresses periodically.
  • Follow Sending Limits:
    Respect limits (e.g., Google: max 20 per hour; Outlook: max 10 per hour).
  • Humanize Your Sender Address:
    Avoid no-reply addresses to build trust.

6. Write Emails That Pass Spam Filters

  • Avoid Spam Trigger Words:
    Steer clear of words like “Free,” “Urgent,” or “Act Now” in your subject line.
  • Keep Subject Lines Short & Personalized:
    Aim for under 7 words to boost engagement.
  • Prefer Plain Text Over Heavy HTML:
    Limit images and heavy formatting.
  • Limit Links & Attachments:
    Use no more than 1-2 links, or none at all.
  • Maintain a Natural Structure:
    Write as if you’re having a conversation—not like a sales pitch.

7. Increase Engagement to Boost Inbox Placement

  • Encourage Replies:
    Ask a simple, personalized question that invites a response.
  • Vary Follow-Up Times:
    Send follow-ups on different days and times to find what works best.
  • Space Out Your Emails:
    Give at least 2-3 days between follow-ups.
  • Use a Smart Signature:
    Include contact info without cluttering the email with too many links.
  • Test Sending Times:
    Experiment with different times to see when your audience is most responsive.

8. Test & Monitor Deliverability (Stay Ahead of Problems)

  • Run Inbox Placement Tests:
    Tools like GlockApps or MailGenius can show you where your emails land.
  • Daily Monitoring:
    Check open and click rates using your email provider’s dashboard.
  • Watch Complaint & Bounce Rates:
    If they creep up, adjust your approach immediately.
  • A/B Testing:
    Regularly test subject lines and content to see what drives better results.

9. Stay Off Blacklists & Fix Spam Issues FAST

  • Regular Blacklist Checks:
    Use MxToolbox, Spamhaus, or Barracuda to ensure you’re not flagged.
  • Immediate Action:
    If you’re on a blacklist, remove yourself as soon as possible.
  • Adjust Your Content & Frequency:
    Tweak your emails to reduce complaints and avoid triggering spam filters.
  • Focus on Relevance:
    Only reach out to verified, relevant contacts to maintain a positive sender reputation.

Things to Do First If You’re Already in Spam (New for 2025)

If you discover your emails are already in the spam folder, don’t panic—but act fast. Here’s a straightforward game plan to get you back on track:

1. Halt Your Campaigns:

Immediately pause sending new emails. This stops further damage while you assess the situation.

2. Review Your Metrics:

Take a close look at your open, click, and bounce rates. Sharp drops can help pinpoint the issue and indicate whether a specific campaign or segment is the problem.

3. Scrutinize Your Content:

Evaluate your recent email content for any potential red flags. Look for overly promotional language, excessive links, or heavy formatting that might have triggered spam filters.

4. Check for Blacklisting:

Use services like MxToolbox or Spamhaus to see if your sending IP or domain has been blacklisted. If you’re on a blacklist, follow their removal procedures promptly.

5. Consult Your ESP:

Reach out to your email service provider. They can offer insights into what might have triggered the spam flag and advise on next steps.

6. Draft a Recovery Plan:

Based on what you find, develop a plan. This might mean adjusting your email frequency, cleaning up your contact list, or even temporarily switching to a “softer” campaign that invites engagement without heavy sales language.

7. Test Before Relaunching:

Once you’ve made changes, send test emails to multiple inbox providers. Use inbox placement tools to verify that your emails now land where they should.

By quickly addressing these areas, you can start rebuilding trust with email providers and your subscribers, setting the stage for better deliverability in the future.

Conclusion

By following this Email Deliverability Checklist, you’re not just avoiding spam filters—you’re building long-term trust with email providers, ensuring that every email you send has the highest chance of success.

If incase you’re wondering how to fix the issues raised, check out this Email Deliverability Audit blog.

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