Improving email deliverability with platforms like Klaviyo and major ISPs such as Microsoft and Yahoo hinges on a multi-faceted approach centered on strong technical authentication, meticulous list hygiene, and consistent subscriber engagement. Implementing SPF, DKIM, and DMARC is non-negotiable for proving sender legitimacy. Concurrently, actively managing list quality through double opt-in, segmentation, and removal of unengaged subscribers is critical, as these ISPs heavily weigh engagement metrics and complaint rates to determine inbox placement.
12 marketer opinions
Sustained email deliverability across platforms like Klaviyo and major ISPs such as Microsoft and Yahoo requires a proactive and continuous focus on refining sending practices. This involves optimizing new sender warm-up processes, segmenting audiences rigorously based on their engagement, and leveraging platform-specific tools for monitoring and issue resolution, all aimed at nurturing a robust sender reputation through consistent positive subscriber interactions.
Marketer view
Email marketer from Email Geeks suggests monitoring Outlook SNDS and postmaster tools, running signups through verification, protecting signup forms, and segmenting sources for testing to identify gaps in bad signups. He also advises seeking direct access to SNDS for dedicated IPs and notes that Microsoft often requires persistent follow-up when reporting issues.
2 Apr 2023 - Email Geeks
Marketer view
Email marketer from Email Geeks highlights that data quality problems can arise from more than just buying lists.
22 May 2025 - Email Geeks
4 expert opinions
To significantly improve email deliverability, especially with major providers like Microsoft and Yahoo and when using platforms such as Klaviyo, a comprehensive strategy is essential. This approach centers on robust email authentication, maintaining an excellent sending reputation through low complaint rates and high subscriber engagement, and meticulously managing data quality. Direct communication with ISP postmaster teams is also highlighted as a vital troubleshooting step for persistent issues.
Expert view
Expert from Email Geeks explains that many are experiencing issues with Microsoft and emphasizes that segmentation and audience selection are crucial, advising to ensure the audience is active and engaged.
21 Jun 2023 - Email Geeks
Expert view
Expert from Email Geeks advises contacting Microsoft and Yahoo postmaster teams, noting Yahoo is generally helpful. She suggests that if other steps fail, the problem is likely data quality, recommending reducing sending to current inboxes and then ramping up with a modified warmup.
5 Jun 2023 - Email Geeks
3 technical articles
Improving email deliverability across major platforms like Klaviyo and key ISPs such as Microsoft and Yahoo consistently requires a foundation of strong technical authentication coupled with diligent list management and an unwavering focus on subscriber engagement. Senders must prioritize maintaining a pristine reputation by adhering to industry standards, ensuring valid DNS configurations, and providing clear unsubscribe options, all while carefully segmenting audiences and utilizing double opt-in to cultivate high-quality, engaged subscriber bases.
Technical article
Documentation from Klaviyo Help Center explains that improving email deliverability involves maintaining a clean list, authenticating your sending domain (SPF, DKIM, DMARC), sending consistent volume, monitoring engagement, segmenting your audience, and using double opt-in for new subscribers.
13 Dec 2024 - Klaviyo Help Center
Technical article
Documentation from Outlook.com Postmaster shares that senders should adhere to industry standards, ensure valid reverse DNS records, maintain a good IP and domain reputation, avoid sending to spam traps, provide a clear and easy unsubscribe mechanism, and only send emails that recipients desire.
24 Apr 2023 - Outlook.com Postmaster
How can I improve email deliverability with Microsoft and avoid spam filters?
What are best practices for improving email deliverability when using Mautic and SMTP.com?
What are the best practices for email deliverability and avoiding spam filters?
What are the best practices for email testing to avoid deliverability issues?
What are the best practices for improving email deliverability to Microsoft Outlook and Hotmail?
What are the top email deliverability best practices for Yahoo and shared DKIM domains?