Summary
The choice of an Email Service Provider (ESP) can indeed influence email deliverability, particularly for crucial operational emails. While an ESP provides the infrastructure and technical capabilities, it is not the sole determinant of whether your emails reach the inbox. Many factors come into play, including the ESP's IP reputation, its technical configurations, and critically, your own sending practices and domain reputation. Operational emails, despite their importance, are not exempt from these deliverability rules and are subject to the same filtering mechanisms as marketing emails. Therefore, understanding the interplay between your ESP and your sending habits is essential for consistent inbox placement.
Key findings
- ESPs manage technical connectivity: ESPs are responsible for Message Transfer Agent (MTA) tuning, including connection rates and retries, which impacts how emails are sent.
- IP reputation matters: Some blocklists can list entire IP ranges belonging to an ESP, potentially affecting users on those shared IPs. Even with a dedicated IP, if others on the same subnetwork send poor quality mail, it can impact your reputation.
- Domain reputation is key: While IP reputation plays a part, your own domain reputation, content relevance, and authentication (like SPF, DKIM, and DMARC) are far more significant determinants of deliverability.
- Operational emails are not immune: Despite their transactional nature, operational emails (e.g., billing, scheduling) are subject to the same filtering and reputation checks, meaning ESP choice and sending practices still apply.
- Platform limitations: Some ESPs may have technical defaults or limitations concerning custom domains, PTR records, or bounce handling that can impact deliverability.
- Layered defense: ISPs use a layered defense approach. Known bad IP or ASN range checks are computationally inexpensive and can lead to immediate blocking for the worst offenders, even if sparingly applied.
Key considerations
- Assess current issues: Before attributing deliverability problems solely to an ESP, verify if you are actually experiencing issues. Sometimes, perceived problems are based on misconceptions or flawed testing. An average deliverability rate across ESPs is around 83.1%, but this varies. Learn more about choosing a good ESP.
- Focus on sender practices: Your practices, including list quality, content relevance, and engagement strategies, typically have a greater impact than the ESP itself. Understand how email deliverability works.
- Evaluate ESP competence: Ensure your ESP effectively manages its MTAs and handles technical aspects, like bounce classification, correctly. A competent ESP provides a solid foundation.
- Understand IP allocation: If using a shared IP pool, be aware of the 'neighborhood' effect. For high volume or critical sends, a dedicated IP might be a better choice to isolate your reputation.
What email marketers say
Email marketers often find themselves debating the direct impact of their ESP on deliverability. Many acknowledge that while the ESP provides the essential sending mechanism, the ultimate responsibility for inbox placement heavily relies on the sender's own efforts. There's a common observation that perceived ESP-related deliverability issues often stem from inadequate sending practices or mishandled transitions between platforms, rather than inherent flaws in the ESP itself.
Key opinions
- ESPs provide technical foundations: Marketers recognize that ESPs handle the technical connectivity and mailing infrastructure.
- Deliverability tied to sender practices: The consensus is that a sender's practices, domain reputation, and content relevance are more influential than the ESP's brand. Your email sending practices significantly impact domain reputation.
- Shared IP risks: Marketers using shared IP pools acknowledge the risk of being affected by other senders' bad behavior on the same IPs. This can even lead to being put on a blacklist (or blocklist).
- Switching ESPs can worsen deliverability: It is often observed that switching ESPs, even to a competent one, can temporarily lead to worse deliverability due to changes in IP address and transition mishaps. Switching ESPs impacts your deliverability rate.
Key considerations
- Don't solely blame the ESP: Many marketers, after becoming more educated, realize that issues initially attributed to the ESP were actually their own doing (e.g., poor list hygiene, irrelevant content).
- Consider dedicated IPs: For significant volumes, especially of operational emails, a dedicated IP can isolate your sending reputation from that of other clients on the ESP. Agencies often use separate IPs per client.
- Verify deliverability claims: Be cautious of deliverability ranking tools or claims. High open rates on a specific mailbox provider (like Gmail) can contradict low deliverability scores from testing tools, indicating the tool might be inaccurate.
- Beware of scare tactics: Sometimes, advice against a particular ESP may be a tactic to sell alternative services or simply misinformed.
Marketer view
Marketer from Email Geeks explains that if you have a dedicated IP, a flawless sender reputation, and non-spammy content, some emails might still go to spam simply because inbox providers recognize the ESP’s servers and flag them based on IP range reputation.
Marketer view
Marketer from Quora notes that an ESP can affect deliverability in several ways, including how they manage technical connectivity, their default settings, and issues with custom domains or bounce handling. These factors are important for email marketing messages to reach their destination.
What the experts say
Deliverability experts largely agree that while an ESP's technical infrastructure and management are important, they are rarely the primary cause of deliverability issues for a diligent sender. The emphasis is consistently placed on the sender's own domain reputation, email authentication, and overall sending practices. Experts note that broad-brush blocklists targeting ESP IP ranges are generally used sparingly by major inbox providers, as they often block legitimate mail.
Key opinions
- Technical impact is minimal for good senders: While ESPs technically can affect deliverability (e.g., through blocklists of entire IP ranges), this typically doesn't impact good senders on higher-quality shared pools or dedicated IPs. Learn more about how authentication and dedicated IPs affect deliverability.
- Sender reputation dominates: Deliverability is largely driven by your own domain reputation, content relevance, authentication, and recipient engagement. This is critical for getting mail to the inbox.
- IP neighborhood effect: Less sophisticated mailbox providers may consider IP range reputation, meaning if poor senders use the same subnetwork, it can lower your sender reputation, even with a dedicated IP.
- Layered defense priority: Anti-spam systems use layered defenses, with IP/ASN range checks being least computationally expensive but also the broadest. They are used for the 'worst of the worst' to cut off connections, not as a primary filter for legitimate mail.
- Platform quality variance: Some ESPs (and their underlying MTAs) manage technical aspects, like bounce handling and error classification, better than others.
Key considerations
- Evaluate ESPs carefully: When choosing an ESP, look for one that handles technical connectivity and bounce classification effectively. Don't fall for deliverability rankings based on platform alone.
- Prioritize your practices: No matter the ESP, if your email content is 'garbage' or your sending practices are poor, even the best ESP will struggle to deliver your mail. This is why ISPs track engagement.
- Understand the IP dynamic: For true isolation from other senders, using IPs from your own subnet or Autonomous System Number (ASN) provides the highest level of control over IP reputation.
- Beware of biased advice: Be skeptical of claims that primarily blame an ESP without thoroughly investigating your own data and practices, as this can sometimes be a sales tactic or misinformed opinion.
Expert view
Expert from Email Geeks explains that ESPs will technically manage connectivity from their MTA, and the tuning of these systems (connections, rates, retries) is crucial. While NOC engineers generally handle this well, some lesser-known domains or servers may still experience issues.
Expert view
Expert from Spamresource.com advises against trusting ESP deliverability rankings, asserting that if such rankings are true, they are incidental and reflect client practices rather than any intrinsic magic of the platform. The real differentiator is the sender's data and practices.
What the documentation says
Official documentation and guides from major email service providers and deliverability platforms consistently highlight the multifaceted nature of email deliverability. They emphasize that while an ESP offers the necessary tools and infrastructure, it is the combination of solid technical configuration (like authentication), healthy sender reputation, and consistent engagement that truly determines inbox placement. The focus is always on best practices that empower the sender, rather than solely on the ESP as the primary deliverability driver.
Key findings
- ESPs enable bulk sending: An ESP provides the technology to build email lists and send campaigns to an audience, making large-scale email communication possible.
- Deliverability is nuanced: Email deliverability involves multiple factors beyond just sending, including successful arrival in the inbox versus merely delivery to the server.
- Reputation management: ESPs manage and monitor deliverability issues, helping users understand their sending metrics and reputation, but the core responsibility lies with the sender to maintain a good standing. Many ESP capabilities are essential.
- ISP relationship: ISPs (Internet Service Providers) can heavily influence email campaigns, necessitating senders to educate themselves and build a healthy relationship with them.
- Authentication importance: Proper email authentication (SPF, DKIM, DMARC) is crucial for deliverability and is a core component ESPs support. This also includes proper DMARC setup.
Key considerations
- Choose ESPs with proven track records: When selecting an ESP, prioritize those with established reputations for high deliverability rates and features that support best practices.
- Align ESP and ISP efforts: Aligning your ESP’s capabilities with ISP requirements (like Gmail’s and Outlook’s 2024 guidelines) is essential for successful campaigns.
- Monitor performance: ESPs allow tracking of deliverability based on recipient server response, opens, and clicks. Utilize these metrics to assess and improve your email program.
- Continuous education: Given the evolving nature of spam filters and ISP requirements, staying informed about best practices is vital for maintaining good deliverability.
Technical article
Documentation from Klaviyo Help Center explains that email deliverability is a nuanced concept influenced by several factors. It highlights that an email's successful arrival in the inbox depends on many elements beyond merely sending the message.
Technical article
Documentation from Mailmodo.com states that ISPs can significantly affect email campaigns, either positively or negatively. It stresses the importance for senders to educate themselves and actively work to maintain a healthy relationship with these providers to ensure emails are delivered effectively.
Related resources
15 resources
Related pages
How do Internet Service Providers track email engagement and its impact on deliverability?
How do ESPs impact deliverability on dedicated IPs?
How do SPF, DKIM, DMARC, and dedicated IPs affect email deliverability when using a third-party ESP?
How does email deliverability work in the current email marketing landscape?
What ESP capabilities are essential for email authentication and deliverability insights?
How do email sending practices impact domain reputation and deliverability?
What is the division of email deliverability responsibility between ESPs and businesses?
How does changing ESPs and domains affect sender reputation and email deliverability?
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