Email Deliverability Best Practices: How to Reach the Inbox
Email deliverability determines whether your messages reach the inbox, the spam folder, or get blocked entirely. Even with correct authentication, poor sending practices can damage your sender reputation.
Start with proper authentication
SPF, DKIM, and DMARC are the foundation of email deliverability. Without them, receiving servers cannot verify your identity.
- Publish a complete SPF record
- Enable DKIM signing for all outbound mail
- Deploy DMARC and monitor reports
Protect your sender reputation
Mailbox providers track how recipients interact with your messages. Complaints, bounces, and ignored emails hurt your reputation.
- Send only to users who opted in
- Remove hard bounces immediately
- Avoid purchased or scraped email lists
Send consistently
Sudden spikes in volume are a common cause of spam filtering. Gradually warm up new domains and IP addresses.
- Start with low volume and increase slowly
- Keep a predictable sending schedule
- Segment large campaigns over time
Optimize email content
While content alone does not determine spam placement, poor formatting and aggressive language can trigger filters.
- Use clean HTML and plain-text alternatives
- Avoid misleading subject lines
- Balance text and images
- Include a visible unsubscribe link
Monitor engagement signals
Opens, replies, and clicks indicate trust. Low engagement signals mailbox providers that your messages are unwanted.
- Remove inactive recipients periodically
- Encourage replies and interactions
- Resend carefully to non-openers
Deliverability checklist
- SPF, DKIM, and DMARC configured correctly
- Consistent sending patterns
- Clean opt-in lists only
- Clear unsubscribe and contact info
- Regular monitoring of bounce and complaint rates
