Does sending emails from multiple systems affect deliverability?

Key findings

• Authentication is key: Properly configured SPF, DKIM, and DMARC for all sending systems is crucial to maintain trust with mailbox providers.
• Reputation management: Sender reputation is built on consistent, positive engagement. Fragmented sending can make it harder to maintain a unified and positive reputation, potentially leading to deliverability issues like emails going to spam or being blocklisted.
• Unsubscribe process: A clear, unified, and promptly honored unsubscribe process across all sending platforms is paramount to prevent spam complaints and maintain subscriber trust. Multiple unsubscribe links or confusing processes can increase user frustration and lead to complaints.
• Categorization of mail: Differentiating between transactional and marketing emails, and potentially sending them from separate systems or dedicated IPs, can protect the deliverability of critical communications from the impact of marketing email performance.

Key considerations

• Centralized oversight: Implement a centralized strategy for managing all email sending, regardless of the system used. This includes consistent branding, content quality, and monitoring of deliverability metrics.
• Consistent authentication: Ensure all domains and subdomains used for sending are correctly authenticated. This helps build a cohesive sender identity, even with various sending systems.
• Subscriber experience: Prioritize a seamless subscriber experience, especially regarding unsubscribes. A single, easy-to-use unsubscribe mechanism for all email types is highly recommended.
• Monitor reputation: Continuously monitor your sender reputation across all IPs and domains. Tools like Google Postmaster Tools can help track key metrics and identify potential issues.
• Separate sending for different types of mail: Consider using different domains or subdomains for different types of email (e.g., transactional versus marketing) to isolate reputation risks. This can help protect critical email streams.

Key opinions

• Spam complaint risk: Marketers frequently highlight that if subscribers have to unsubscribe multiple times or encounter a disconnect due to varied sending systems, it can lead to a spike in spam complaints, which directly impacts deliverability.
• Common practice: Many marketers acknowledge that using multiple systems for different email types (e.g., transactional, marketing, surveys) is not uncommon and can be managed effectively with clear delineation and proper authentication.
• Tracking engagement challenges: A messy setup with emails from various third-party systems, especially without a well-linked unsubscribe process, makes tracking overall subscriber engagement throughout their lifecycle extremely difficult.
• Consolidation benefits: There is a general sentiment that consolidating email sending into a main ESP can streamline operations and improve tracking.

Key considerations

• Unified unsubscribe: Regardless of the number of sending systems, ensure a single, consistent, and easy-to-use unsubscribe mechanism. This is critical to reduce complaints and improve overall email deliverability. For more on managing links, see how multiple links affect deliverability.
• Clear content delineation: Establish clear boundaries for what each system sends. For instance, customer care systems should not send promotional content. This helps manage subscriber expectations.
• Aligning sender identity: Even with multiple systems, aim for a cohesive sender identity (e.g., using the same 'from' name and branding) to avoid confusion and bolster your sender reputation. Consider if the same 'from' name causes issues.
• Risk assessment: Regularly assess the deliverability impact of each sending system. Problems in one system can potentially affect the overall sender reputation, even for mail sent from other platforms. More information can be found on factors affecting email deliverability.

Key opinions

• Authentication priority: Experts consistently stress that proper authentication (SPF, DKIM, DMARC) is the most critical factor, overriding concerns about the number of sending systems. Learn more about a simple guide to DMARC, SPF, and DKIM.
• Reputation is paramount: Sender reputation is determined by recipient perception and engagement. While multiple systems can introduce more opportunities for mistakes, they do not automatically lead to a negative reputation.
• Unsubscribe compliance: Failure to honor unsubscribe requests promptly, regardless of which system sent the email, will lead to spam filter issues, ESP terms of service violations, and potential legal problems. A quick (preferably 24-hour) unsubscribe process is vital.
• Operational challenges: The main risks from multiple systems are operational inefficiencies and increased chances for errors that could harm deliverability.

Key considerations

• Unified unsubscribe management: Ensure that all unsubscribe requests are processed across all sending systems seamlessly and quickly. This is crucial for avoiding spam complaints and maintaining good standing with mailbox providers.
• Consistent sender identity: Maintain consistent sender details (e.g., 'From' address, domain) and branding across all platforms to avoid confusing recipients and to build a strong, unified sender reputation.
• Proactive monitoring: Monitor your sender reputation comprehensively across all IPs and domains to quickly identify and address any issues. Understanding how your email address ends up on a blacklist can help.
• Authentication enforcement: Rigorously implement and enforce SPF, DKIM, and DMARC for every sending system and subdomain. This validates legitimate emails and protects your domain from unauthorized use. More insights are available from trusted deliverability experts.

Key findings

• Authentication standards: RFCs and postmaster guidelines consistently highlight SPF, DKIM, and DMARC as fundamental for verifying sender identity and preventing spoofing, irrespective of the sending platform.
• Sender reputation assessment: Mailbox providers assess sender reputation at both the IP and domain level. All sending systems contribute to this collective reputation, meaning inconsistent practices on one platform can negatively affect the others.
• Unsubscribe requirements: Compliance documentation stresses the legal and technical necessity of providing a clear and functional unsubscribe mechanism, which must be universally honored across all sending points.
• Policy enforcement: DMARC policies (e.g., p=quarantine or p=reject) apply to all emails sent from a domain, meaning all systems must comply with the established authentication and alignment rules to avoid rejection.

Key considerations

• Comprehensive DMARC implementation: Implement DMARC for your domain and configure it to monitor all sending sources. This provides crucial visibility into all email streams and helps identify unauthorized sending or misconfigurations. See the benefits of implementing DMARC.
• Consistent technical setup: Ensure that SPF records include all legitimate sending IP addresses or domains and that DKIM signatures are correctly applied by every platform sending on your behalf.
• Adherence to local laws: Ensure that all systems comply with relevant email marketing regulations (e.g., CAN-SPAM, GDPR, CASL) concerning consent, unsubscribe options, and transparent sender identification.
• Domain separation strategies: Consider using subdomains for different email categories (e.g., transactional.yourdomain.com, marketing.yourdomain.com) to help segment reputation and minimize cross-impact, as suggested in various deliverability improvement guides.