Email Deliverability Best Practices: Get Your Emails Into the Inbox

Email marketing only works if emails actually reach inboxes. Poor deliverability means your carefully crafted messages end up in spam folders—or get blocked entirely. Understanding and optimizing deliverability is essential.

What Affects Deliverability

Email providers (Gmail, Outlook, etc.) evaluate many factors when deciding where to place your email:

• Sender reputation
• Authentication setup
• List quality and engagement
• Content and formatting
• Sending patterns

Authentication Setup

Authentication proves you're authorized to send from your domain. Without it, emails are more likely to be marked as spam.

SPF (Sender Policy Framework)

SPF specifies which mail servers can send email on behalf of your domain. It's a DNS record that email providers check.

DKIM (DomainKeys Identified Mail)

DKIM adds a digital signature to your emails, proving they haven't been tampered with in transit.

DMARC (Domain-based Message Authentication)

DMARC tells email providers what to do if SPF or DKIM checks fail. It also provides reporting on authentication results.

Why All Three Matter

Major email providers increasingly require all three. Gmail and Yahoo announced stricter requirements for bulk senders starting in 2024.

If you're not sure about your authentication setup, use tools like MXToolbox or Mail-Tester to check.

List Hygiene

Remove Invalid Addresses

Sending to addresses that bounce hurts your sender reputation. Clean your list regularly by removing:

• Hard bounces (invalid addresses)
• Addresses that repeatedly soft bounce
• Obvious typos (gmal.com, yaho.com)

Remove Unengaged Subscribers

Subscribers who never open emails signal to providers that your content isn't wanted. Periodically remove or re-engage subscribers who haven't opened emails in 6-12 months.

Use Double Opt-In

Double opt-in ensures subscribers actually want your emails, reducing spam complaints and bounces.

Never Buy Lists

Purchased lists contain people who didn't opt in. They'll mark you as spam, destroying your sender reputation.

Sending Practices

Consistent Volume

Dramatic spikes in email volume trigger spam filters. If you normally send 1,000 emails weekly, suddenly sending 50,000 looks suspicious.

Warm Up New Domains/IPs

New sending infrastructure needs to build reputation gradually. Start with engaged subscribers and slowly increase volume.

Maintain Regular Sending

Long gaps between emails hurt deliverability. Subscribers forget they signed up and mark you as spam.

Send at Appropriate Times

Sending in the middle of the night (recipient's time) can look suspicious. Send when subscribers would normally receive business email.

Content Best Practices

Avoid Spam Trigger Words

Certain words and phrases trigger spam filters:

• "Free," "Act now," "Limited time"
• Excessive punctuation (!!!)
• ALL CAPS
• "Click here" as link text

Balance Text and Images

Image-only emails often go to spam. Include sufficient text content.

Include Unsubscribe Link

Legal requirement in most countries, and emails without it are more likely to be flagged as spam.

Use a Recognizable From Name

Recipients should recognize who the email is from. Unfamiliar sender names lead to spam reports.

Monitoring Deliverability

Key Metrics to Track

Bounce Rate: Should be under 2%. Higher indicates list quality issues.

Spam Complaint Rate: Should be under 0.1%. Higher indicates content or consent issues.

Open Rate: Declining open rates may indicate deliverability problems.

Inbox Placement Rate: Percentage of emails that reach the inbox (not spam). Use tools like GlockApps or 250ok to test.

Use Seed List Testing

Send to test addresses across major providers before campaigns to verify inbox placement.

Monitor Blacklists

Check if your domain or IP is on email blacklists. Tools like MXToolbox can check multiple blacklists at once.

Handling Deliverability Problems

Sudden Drop in Open Rates

1. Check for blacklisting
2. Verify authentication is working
3. Review recent content changes
4. Check bounce and complaint rates

High Bounce Rate

1. Clean your list immediately
2. Implement email verification on signup
3. Check for list import errors

Landing in Spam

1. Run content through spam checkers
2. Review authentication setup
3. Check sender reputation with tools like Sender Score
4. Consider warming up again with engaged segment

Key Takeaways

• Authentication (SPF, DKIM, DMARC) is essential for deliverability
• Clean your list regularly to remove bounces and unengaged subscribers
• Never buy email lists—it destroys sender reputation
• Maintain consistent sending volume and frequency
• Avoid spam trigger words and image-only emails
• Monitor bounce rates, complaint rates, and inbox placement
• Act quickly when deliverability problems appear

Ready to Get Started?

Deliverability determines whether your email marketing actually reaches your audience. But even perfect deliverability requires great content and strategy to drive results.

That's exactly why we're building Blyra—to bring email automation, landing pages, and forms together in one platform. When your email marketing is connected to your entire funnel, you can build engaged lists that providers trust. Join our waitlist to be among the first to try it.