How Your ESP Affects Your Deliverability: The Real Story
How Your ESP Affects Your Deliverability: The Real Story


When it comes to email marketing, your Email Service Provider (ESP) plays a crucial role in ensuring your messages reach your recipients’ inboxes. But have you ever wondered how your ESP affects your email deliverability? In this blog post, we’ll provide your marketing team with a crisp and clear understanding of how your ESP can impact your email deliverability and share some best practices to improve it. Let’s dive in and uncover the real story behind ESPs and deliverability.

ESP Reputation and Infrastructure:
Your ESP’s reputation and infrastructure have a significant impact on your email deliverability. Here’s what you need to know:


  • ISP Relationships: Established ESPs often have established relationships with Internet Service Providers (ISPs), which can help improve deliverability by ensuring your emails are recognized as trustworthy.
  • Sender Reputation: ESPs maintain sender reputation metrics, such as sender IP reputation, domain reputation, and email engagement rates, which can affect how ISPs perceive your emails.


  • Server Infrastructure: ESPs with robust server infrastructure and dedicated IP addresses can help maintain deliverability by reducing the risk of sharing IPs with other senders who may have a poor sending reputation.
  • Authentication: ESPs that support authentication protocols like SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) can enhance deliverability by providing additional verification and trust to ISPs.
  • Deliverability Tools and Support:

    The deliverability tools and support offered by your ESP are vital in managing and improving your email deliverability. Consider the following:

Deliverability Monitoring:

  • Reporting and Analytics: Effective ESPs provide detailed reporting and analytics on email delivery rates, bounces, opens, and click-through rates, enabling you to monitor and optimize your campaigns.
  • Spam Filter Testing: ESPs that offer spam filter testing tools help you identify potential issues that might cause your emails to land in spam folders, allowing you to make necessary adjustments.

Support and Guidance:

  • Deliverability Experts: Some ESPs have dedicated deliverability teams or experts who can provide guidance and assistance in improving your email deliverability.
  • Best Practice Recommendations: Reliable ESPs offer best practice recommendations and resources to help you optimize your email content, structure, and sending practices to comply with industry standards and ISP guidelines.
  • List Management and Engagement:

    How you manage your email list and engage with your subscribers also affects your deliverability. Here are some considerations:

List Hygiene:

  • Permission-Based Practices: ESPs that enforce and encourage permission-based practices, like double opt-ins, help ensure your emails are sent to engaged recipients who are more likely to open and interact with your messages.
  • List Segmentation: Segmenting your email list allows you to send more targeted and relevant content to specific groups, improving engagement and reducing the risk of triggering spam filters.


  • Open and Click Rates: ESPs consider metrics like open rates and click-through rates when evaluating sender reputation. Higher engagement indicates a positive sender reputation, potentially leading to better deliverability.
  • Unsubscribe and Complaint Rates: Monitoring unsubscribe and complaint rates is crucial. High rates can signal issues with your content, frequency, or targeting, potentially impacting deliverability.


Your ESP choice has a direct impact on your email deliverability. A reputable ESP with strong ISP relationships, robust infrastructure, authentication support, and deliverability tools can significantly improve your chances of reaching the inbox. Leveraging deliverability support, monitoring, list management best practices, and engaging content can further enhance your deliverability rates.

Remember to regularly monitor and analyze your email performance, adjust your strategies based on feedback, and stay informed about industry best practices. By understanding how your ESP affects your deliverability and implementing the right practices, you can optimize your email campaigns and maximize the effectiveness of your marketing efforts.