The Spam Resource Guide to Klaviyo Deliverability Success

Introduction

Email deliverability success is essential for ensuring your messages reach your subscribers' inboxes. For Klaviyo users, understanding best practices can significantly improve engagement and overall email success. This guide outlines key concepts, best practices, and actionable steps to optimize your Klaviyo email deliverability.

Understanding Delivery vs. Deliverability

Delivery refers to whether an email was accepted by the recipient’s mail server, but it doesn’t indicate inbox placement. Deliverability success means that emails land in the inbox rather than the spam folder, making engagement metrics like opens and clicks crucial indicators of success.

If you're looking purely (and only) at the delivery stats in Klaviyo, or any other email service provider platform, remember that they're not able to tell which folder mails land in as they're being delivered. Inbox placement can be tricky to measure. Some marketers utilize seedlist testing. Look for very low open rates as a potential indicator of spam folder placement (even in modern "Apple MPP" times).

Sign up for your own list and look in that mailbox to see where email messages are landing. Filtering can sometimes be individualistic (meaning not every recipient ends up with the same filter result) but this can still be useful.

Factors Affecting Email Reputation

Your email reputation influences whether mailbox providers like Gmail and Yahoo filter your emails as spam. Key factors include:

• Spam complaints – High complaint rates damage reputation. Are you sending wanted mail? Did subscribers sign up knowingly? Were you clear with cadence and content declarations?
• Bounce rates – Sending to invalid addresses is bad news. Besides the deliverability risk, high bounces signal to Klaviyo that you have list hygiene issues and might not be in compliance with their policies and requirements.
• Engagement – Low open and click rates suggest unwanted emails. Low engagement is a key underlying cause of spam folder placement.
• Sending consistency – Erratic sending patterns can trigger spam filters. Unexpected email volume spikes are suspicious.

Best Practices for Klaviyo Deliverability

Here are the primary considerations you'll want to keep in mind when working to reliably reach the inbox as you send email marketing campaigns via Klaviyo.

1. Focus on Engagement. Segment audiences based on recent engagement (e.g., last 30-90 days). Suppress inactive subscribers to maintain a clean list. Use win-back campaigns to re-engage dormant contacts before removing them.
2. Optimize Engagement Segmentation based on Send Frequency. Adjust email frequency based on subscriber engagement levels. For daily senders, look to engage with subscribers active in the last 30 days. Go up from there. Sending 2-4 times weekly? Your audience focus should be on those engaged within the past 60 days. Weekly senders? You can up it yet again. Focus on subscribers engaged within the past 180 days.
3. Authentication Matters. Proper email authentication improves credibility and is mandated by mailbox providers nowadays. SPF, DKIM, and DMARC should be correctly configured. Use a dedicated sending domain in Klaviyo for better reputation control. Align click tracking with a dedicated tracking domain.
4. IP Address Strategy. Sending 1M+ emails/month? Dedicated IP is the way to go, but keep in mind that this requires a specific warming strategy. Lower-volume or inconsistent senders are likely better off on shared IP addresses.
5. Avoid cousin domains. Stick to your primary brand domain rather than using similar variations (e.g., brand-mail.com). Instead, use subdomains like “email.brand.com” to separate marketing and transactional emails. Lookalike alternate domains can drive confusion and bad actors can and do exploit this.
6. Adjust for the new world order of Apple Mail Privacy Protection (MPP). Use clicks over opens as an engagement metric. Filter MPP-inflated opens in Klaviyo segmentation. Monitor engagement trends using A/B testing.
7. Monitor Performance by Mailbox Provider. If deliverability drops at a specific provider (e.g., Gmail vs. Outlook), segment by domain and adjust strategies accordingly.
8. Never Use Purchased Lists. Avoid using purchased or scraped email lists, as they damage sender reputation and lead to spam traps. Use email verification tools to maintain clean data.

More on that Custom Domain

Which of these matter most? They’re all important things to keep in mind, but if I had to focus on one single thing that has the most positive impact on deliverability, assuming you’re a good email sender, it’s going to be the dedicated sending domain, aka branded sending domain configuration in Klaviyo. This is vitally important so that you can stand out on your own in the eyes of mailbox providers. Let Gmail see you as you, and build a reputational view of what you’re doing as a standalone entity. Without this, your domain reputation is blended with that of all other Klaviyo clients, and this is not necessarily to your benefit.

Go here to learn more about configuring a branded sending domain in Klaviyo.

And Finally

Deliverability is about sending wanted emails to engaged recipients. By following these best practices and leveraging Klaviyo’s tools, you can ensure strong inbox placement, better engagement, and improved ROI on your email marketing efforts.

Looking for an overview of Klaviyo Deliverability Best Practices via a video? Find my previous recorded webinar here. 

Special thanks to Tonya Gordon for her help and expertise compiled and shared on the Klaviyo webinar.