Email Deliverability Best Practices
Learn the difference between email delivery and inbox placement. Explore best practices for authentication, list hygiene, and content analysis.
Email deliverability is the practice of ensuring your messages reach the intended recipient. It requires distinguishing between delivery and inbox placement. Delivery means the receiving provider accepted the message without a bounce. Inbox placement means the receiving provider routed the accepted message to an inbox category or another non-spam folder, rather than a spam or junk folder. Proper authentication, a strong sender reputation, and clean message content work together to help your emails reach the inbox.
Authentication and Alignment
Proper email authentication proves your identity to receiving servers and prevents domain spoofing. You must configure Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM). SPF lists the IP addresses authorized to send on behalf of your domain. DKIM adds a cryptographic signature to your messages, ensuring the content remains unaltered during transit.
Domain-based Message Authentication, Reporting, and Conformance (DMARC) ties SPF and DKIM together. DMARC alignment requires the domain in your visible sender address to match the domain validated by SPF or DKIM. A basic policy looks like v=DMARC1; p=none; rua=mailto:reports@example.com;. You can read the technical specifications in DMARC RFC 7489 and the IETF DMARC RFC record. For help preparing or checking record text, use our DMARC Record Wizard.
Permission and List Hygiene
Never send emails to users who did not explicitly opt in. High complaint rates severely damage your sender reputation. You must process bounces immediately. Hard bounces indicate a permanent failure, such as an invalid address, and you must remove these from your list. Soft bounces indicate temporary issues, like a full mailbox, but repeated soft bounces require removal.
Provide a clear and simple unsubscribe mechanism. The Gmail sender guidelines require one-click unsubscribe headers for bulk senders. Making it difficult to unsubscribe increases the likelihood that users will mark your message as spam, which harms your future deliverability.
Sending Consistency and Content
Erratic sending volumes trigger spam filters. Warm up new IP addresses and domains by gradually increasing your sending volume over several weeks. Maintain a consistent schedule to establish predictable behavior.
Message content also influences routing decisions. SendRepute analyzes your sender name, subject, body text, links, formatting, and HTML signals before you send a message. We provide a probabilistic spam classification, confidence estimates, and highlight detected terms when your account permits. The result is an analysis of content spam risk to help you prepare stronger emails. You can review these estimates using our Spam Checker Guide. The content classifier analyzes content only, not live DNS or blacklists. Separate Domain Check reads live public DNS and five selected public threat-intelligence sources; it is not a comprehensive check of all DNSBLs or private-provider blocklists. The classifier and builder do not send email. SendRepute Campaigns sends via your own connected provider; SendRepute is not a hosted SMTP delivery service. No tool changes DNS. However, identifying problematic content before sending helps you make informed manual edits or apply safe HTML corrections. We also offer optional AI rewriting in the product to help you draft clearer content.
Pre-Send Checklist
- Verify SPF, DKIM, and DMARC alignment for your sending domain.
- Confirm all recipients provided explicit consent to receive your communications.
- Include a clear unsubscribe link and implement one-click unsubscribe headers.
- Analyze your content for formatting issues and spam signals.
- Check your domain status using our Sender Reputation.
Post-Send Checklist
- Monitor delivery rates and review your bounce logs.
- Remove hard bounces from your database immediately to protect your reputation.
- Track spam complaints and suppress those users from future campaigns.
- Review DMARC reports to identify unauthorized sending sources or authentication failures.
- Adjust your sending volume if you notice throttling or temporary rejections from receiving providers.
Monitoring your metrics is a continuous process. By following established protocols, authenticating your domain, sending to permission-based lists, and resolving spam signals, you build a positive reputation over time and prepare stronger emails.