10+ best practices to improve your email deliverability

Summary

Email deliverability determines whether messages reach inboxes rather than merely being accepted by recipient mail servers, and the guide distinguishes delivery rate from inbox placement. It recommends authenticating domains with SPF and DKIM, using appropriate IP allocation and warm-up, applying double opt-in, writing genuine subject lines, offering preference controls, cleaning lists, avoiding purchased addresses and spam traps, sending valuable content, and monitoring metrics. The stated benchmark for good deliverability is at least 95%, while the excerpt cites Twilio SendGrid's 99% API rate and warns that changing providers does not repair domain or IP reputation. Case studies report Shopify at 99.5% overall delivered and 91.3% inbox placement, and Klaviyo at 99.94% average delivery, with the latter also reporting 1.9-second median delivery speed.

Takeaways

1. 1

   SPF and DKIM authentication help demonstrate to internet service providers that a sender controls its domain and can reduce risks associated with spoofing and poor delivery rates.

2. 2

   The guide recommends using a dedicated IP once sending reaches 25,000 daily emails and warming that IP before sending to the full list; adding IPs to evade penalties can lead to an entire IP pool being blocked.

3. 3

   A deliverability rate of 95% or higher is presented as good, while switching email service providers generally will not fix problems rooted in domain reputation, IP reputation, list quality, engagement, or authentication.