How to Improve Email Deliverability: 15 Proven Strategies That Work

Email deliverability determines whether your emails reach the inbox or vanish into spam folders. It's the single most important metric for email success—because it doesn't matter how great your email is if nobody sees it.

1. Authenticate Your Email Domain

Email authentication is non-negotiable. These three protocols prove you're a legitimate sender:

SPF: Lists which mail servers can send on behalf of your domain
DKIM: Adds a digital signature to your emails
DMARC: Tells receiving servers what to do if authentication fails

2. Build Your List Organically

Never buy email lists. Recipients didn't opt in, so they mark you as spam. This damages your reputation permanently.

3. Use Double Opt-In

Double opt-in verifies email addresses are real and confirms genuine interest. Yes, it reduces list size slightly, but engaged subscribers are worth 100x more than fake ones.

4. Warm Up New Domains

Warm-up schedule:

Week 1: Send to 50-100 engaged subscribers
Week 2: Double your volume (100-200)
Week 3-4: Continue doubling weekly
Monitor bounce and spam rates closely

5. Maintain Consistent Sending

Send on a predictable schedule. Sporadic sending confuses subscribers and ISPs.

6. Clean Your List Regularly

Remove hard bounces immediately
Remove subscribers who haven't opened in 6+ months
Run re-engagement campaigns first

7. Segment Your Audience

Relevant emails get opened. High open rates improve deliverability. Segment by engagement, interests, and lifecycle stage.

8. Write Compelling Subject Lines

Keep under 50 characters
Personalize when possible
Be specific and clear
Avoid ALL CAPS and excessive punctuation

9. Monitor Sender Reputation

Tools:

Google Postmaster Tools (for Gmail)
Microsoft SNDS (for Outlook)
Sender Score (free from Validity)

10. Provide Easy Unsubscribe

Making it hard to unsubscribe backfires. Frustrated subscribers mark you as spam, which is far worse.

11. Balance Text and Images

Best ratio: 60% text, 40% images. Always include alt text.

12. Limit Links

Keep to 3-5 links per email. Use HTTPS. Avoid URL shorteners.

13. Test Before Sending

Professional marketers test every campaign. SPAMRUN lets you test instantly, identifying issues before you hit send.

14. Optimize for Engagement

Write valuable, relevant content
Include clear calls-to-action
Encourage replies (Gmail loves this)
Optimize for mobile

15. Track Key Metrics

Bounce rate: Under 2%
Spam complaint rate: Under 0.1%
Open rate: 20-30% typical
Click rate: 2-5% standard