Description
There are several factors that can direct your email to your junk folder instead of directly to your inbox. Check the following to improve deliverability.
Why It's Important
Following email marketing best practices, like maintaining clean contact lists, sending relevant content to engaged subscribers, and honoring unsubscribe requests, builds trust with email providers, giving you control over your sender reputation and keeping your emails out of spam. Poor practices like buying lists or ignoring engagement signals quickly damage your reputation and land you in the spam folder, regardless of authentication.
Authenticate your sending domain
Domain authentication is absolutely critical because it proves to email providers like Gmail and Outlook that you are who you claim to be and that you're authorized to send emails from your domain. Without authentication, email providers have no way to distinguish you from spammers and scammers, so they protect their users by automatically sending your emails to spam or blocking them entirely.
Think of it like showing your ID at the airport: without proper identification, you simply can't get through. Major email providers now require authentication protocols (SPF, DKIM, and DMARC), and without them, 60-90% of your emails will never reach the inbox, no matter how good your content is. Beyond just reaching the inbox, authentication also protects your brand from being impersonated by malicious actors who could send phishing emails pretending to be you, damaging your reputation and customer trust. In today's email landscape, authentication isn't optional, it's the foundation that makes email marketing work, and without it, you're essentially wasting your time and money sending emails that nobody will ever see.
Content Guidelines
Avoid Spam Words
Avoid overusing "SPAM" words (Free!, gambling-related terms, too many exclamation points, ALL CAPS)
Image Coverage Guidelines
- Maximum 40% image coverage. We recommend having multiple smaller images with clear and descriptive alt text
- Minimum 60% text coverage
- Not all images touching each other
- At least 400 characters of text
According to anti-spam law, all emails must contain some form of text (even if it's a simple "hello").
Benefits of Proper Image/Text Balance
This will help by:
- Preventing the email from being flagged as spam
- Encouraging people to display images
- Helping email loading times
Best Practices
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Follow best practices and use a double opt-in process
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Test your form signup process by signing up yourself to the newsletter and see where it lands
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Make sure your recipients add you to their whitelist or address book
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Ensure your recipients click "always display images from this sender" – this will let the email service know you are a trusted sender
Troubleshooting
My emails still go to spam after following all guidelines
- Check your sender reputation using tools like Google Postmaster or Microsoft SNDS
- Verify that your domain authentication (SPF, DKIM, DMARC) is properly configured
- Review recent campaign metrics for high complaint or bounce rates
- Consider warming up your sending reputation with smaller, engaged segments first
Images don't display even with proper text ratio
- Ensure image file sizes are optimized (under 100KB per image recommended)
- Use standard image formats (JPG, PNG, GIF)
- Host images on a reliable and fast server
- Add descriptive alt text for all images
Recipients report emails as spam despite subscribing
- Review your signup process to ensure clear expectations were set
- Check if your email frequency matches what was promised during signup
- Send a re-engagement campaign to confirm subscriber interest
- Consider implementing preference centers for frequency and content choices
Different email providers treat my emails differently
- Test your emails across multiple providers before sending
- Monitor delivery rates by domain (Gmail, Yahoo, Outlook, etc.)
- Adjust content or sending patterns based on provider-specific issues
- Gradually build sender reputation with each provider
Related Articles
- Authenticate my domain with SPF DKIM and DMARC - Improve reputation
- Master the basics of deliverability - Inbox placement
- Domain blacklisting - Check blacklists
- Understanding complaints, bounces and unsubscribes - Spam complaints
- Test your campaign - Test spam scores