What are the best practices for email deliverability when using SparkPost and Amazon SES, including reverse DNS, blacklist monitoring, and handling dedicated IPs?

Key findings

• Email Authentication: Consistent authentication using SPF, DKIM, and DMARC significantly improves deliverability and sender reputation.
• Reverse DNS (rDNS): Properly configured rDNS that matches your sending domain enhances trust and deliverability, especially with dedicated IPs.
• Sender Reputation: Maintaining a positive sender reputation is crucial, as ISPs use it to determine email acceptance and inbox placement.
• Blacklist Monitoring: Monitoring blacklists, particularly Spamhaus, is vital for identifying and addressing issues affecting sending IPs or domains.
• IP Warming: Warming up dedicated IPs gradually helps establish a positive sending reputation with ISPs.
• Email List Hygiene: Practicing good email list hygiene improves deliverability by removing inactive, invalid, and spam trap addresses.
• Suppression Lists: Suppression lists automatically prevent sending to addresses that have bounced, unsubscribed, or marked emails as spam.
• Email Testing: Email testing tools help identify deliverability issues, such as placement in spam folders, before sending campaigns.
• DMARC Policy: Implementing DMARC policy enforcement prevents unauthorized domain usage and greatly enhances deliverability.

Key considerations

• AWS SES Verification: Verify each email address (sender) before using it to send email through Amazon SES.
• ESP Metrics: If paying SparkPost or SES, leverage their provided user-friendly metrics dashboards for day-to-day monitoring.
• Spamhaus Listings: Getting listed by Spamhaus requires immediate attention, but resolving the issue can lead to quick delisting.
• Bounce Handling: Set up bounce notifications and promptly remove bouncing addresses from your sending lists.
• Engaged Subscribers: Start with your most engaged subscribers when warming up IPs, monitoring bounce rates and spam complaints.
• 2048 Bit DKIM: Implement a 2048-bit DKIM key, which increases security; also, ensure you renew keys regularly.

Key opinions

• Sender Reputation: Maintaining a positive sender reputation is crucial as ISPs use it to determine whether to accept, reject, or filter emails.
• Authentication: Consistently authenticate your emails using SPF, DKIM, and DMARC to improve deliverability.
• Reverse DNS: Properly configure reverse DNS (rDNS) for your sending IPs, especially dedicated IPs, to match your domain and enhance trust.
• Blacklist Monitoring: Regularly monitor blacklists to identify and address any listings affecting your sending IPs or domain.
• IP Warming: When warming up new IPs, gradually increase sending volume to engaged subscribers to establish a positive reputation.
• List Hygiene: Practice good email list hygiene by removing inactive, invalid, and risky email addresses.
• DMARC Enforcement: Implement DMARC policy enforcement to prevent unauthorized use of your domain and enhance sender reputation.
• Email Validation: Use email validation services to remove invalid, risky, and inactive addresses, which will protect sender reputation.

Key considerations

• Dedicated IPs: If sending from IPs through Sparkpost/SES and those IPs appear in Received headers, ensure valid rDNS is set.
• Spamhaus Listing: Being listed on Spamhaus is a significant concern, but prompt action to resolve the issue will lead to delisting.
• Content Relevance: Ensure your email content is relevant and targeted to your subscribers to minimize spam complaints.
• Suppression Lists: Utilize suppression lists (bounces, unsubscribes, spam complaints) to avoid sending to problematic addresses.
• Email Testing: Use email testing tools before sending campaigns to identify and fix deliverability issues.
• Engaged Subscribers: When warming IPs, start with the most engaged subscribers, and increase volume as confidence grows.

Key opinions

• Reverse DNS Configuration: Reverse DNS should match the hostnames of your machine and the name given in the EHLO to avoid filters being wary.
• ESP Monitoring Tools: If using SparkPost or SES, leverage the provided metrics dashboards for day-to-day monitoring of deliverability.
• Blacklist Impact: Spamhaus lists are one of the most impactful public blacklists and can directly effect delivery problems.
• List Management: List management and engagement is key, sending to unengaged users can damage your reputation.
• DKIM Key Size: Using a 2048 bit DKIM key and regular renewal improves deliverability by adding increased security.

Key considerations

• Spamhaus Reputation: Spamhaus has a strong reputation and is widely used due to its reasonable listing policies and professional conduct.
• Bounce Processing: Proper bounce processing and whitelisting of your ESP's IPs are crucial for reliable feedback and to prevent blocking legitimate traffic.

Key findings

• Email Verification: You must verify each sender email address before using it with Amazon SES.
• IP Warming: Gradually increase sending volume over several weeks when using dedicated IPs to establish a positive reputation.
• SPF Records: Set up SPF records by publishing a TXT record to your DNS to authorize mail servers to send on behalf of your domain.
• Suppression Lists: Suppression lists are essential for automatically excluding addresses that have bounced, unsubscribed, or marked emails as spam.
• Bounce Handling: Proper bounce handling is crucial and involves setting up notifications and removing bouncing addresses from your sending lists.
• Feedback Loops: Setting up feedback loops with ISPs allows receiving spam complaint reports to identify and remove problematic subscribers.

Key considerations