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June 7, 2024

Klaviyo Audit Expert Series: Email Deliverability 


  1. The definition and importance of email deliverability: You’ll understand what email deliverability is, why it’s a huge part of your marketing success, and how it affects different aspects of your email marketing.
  2. Things that influence email deliverability: You’ll learn about the various things that affect deliverability, like sender reputation, email authentication protocols, spam filters, email content and design, and recipient engagement.
  3. How to do an email deliverability audit in Klaviyo: You’ll get a step-by-step guide on how to audit your Klaviyo account to find and deal with deliverability issues.
  4. Valuable tools for boosting deliverability: You’ll discover Klaviyo’s handy built-in features and third-party tools we like that can help you optimize your email deliverability. 

Klaviyo users already know the power of email marketing. But are your emails truly reaching their full potential… Or is your hard work being ruined by bad email deliverability? In the competitive e-commerce world, making sure your messages land in the inbox, not the Bermuda triangle spam folder, is kind of a big deal. 

This guide will dive into the nitty-gritty bits of email deliverability within Klaviyo. We’ll check out the (many) things that can influence your deliverability rate, give you an easy step-by-step audit process, and explain how you can use Klaviyo’s features and some useful third-party tools to optimize your campaigns.

What is Email Deliverability? 

Email deliverability is the technical term for how many of your emails land up in your reader’s inbox instead of their spam folder. It’s measured in a percentage; for example, an email deliverability score of 80 means 80% of your emails find the inbox. 

When emails land in the inbox rather than the spam folder, they’re much more likely to be seen, read, and acted upon. If someone’s missed your limited time sale because the promo went to spam, well… You’ve lost a customer that could well have bought from you if they’d only seen your message in time. 

Things like your sender reputation, email content, recipient engagement, and how well you stick to email marketing best practices can all affect your email deliverability.

Why Does Email Deliverability Matter? 

Email deliverability directly affects the success of your marketing campaigns. Poor deliverability means your messages may end up in spam, and if your readers can’t see them, they can’t act on them. Basically, you’re sending messages into a void. 

When your audience doesn’t see, open, or interact with your emails, it can harm your sender reputation, which tells email service providers that your emails are junk. This is a dangerous place to be when your business relies on those emails getting opened. 

Impact on Engagement 

High deliverability rates give you the best chance of your emails being seen by your audience. Higher open rates and more clicks ultimately lead to more conversions. As we’ve already mentioned, a promotional email about a sale will see way better results if the email lands in the inbox rather than the spam folder (which most people don’t check often). 

Customer Relationships

Keeping up a good deliverability score helps build trust with your customers. If your emails consistently pop up in their inbox and provide value, they’re more likely to engage with your brand and remain loyal. 

This is especially important for businesses that rely on repeat customers, like subscription services. It’s like keeping in touch with your friends—if your mobile service provider is blocking your messages, your friends aren’t going to place much stock in your friendship. Same thing with your emails. 

Business Goals

Effective email deliverability supports your big-picture marketing goals. It doesn’t matter what your goal is—to increase sales, boost website traffic, or improve customer retention,—making sure those emails reach the inbox is key. 

Imagine this: an ecommerce company sends onboarding emails to new customers about getting started with their product. If it lands up in the spam folder, their new clients will be unimpressed at the lack of guidance (not realizing it’s basically in their trash can). 

But land it in their inbox, and they’ll start off on a good footing with your product and be more inclined to take an upsell because they know they’ll get good service. 

Reputation Management 

Poor deliverability can do some damage to your sender reputation. Internet service providers spy on sender behavior, and if they spot high bounce rates or spam complaints, it can cause them to assume you’re just spammy… So they’ll put you in the spam folder where (they think) you belong. 

Regularly cleaning your email list and following best practices can help you keep up a good reputation and boost your deliverability.

What Is a Good Email Deliverability Score? 

A good email deliverability score in Klaviyo is between 75 and 89. This means that between 75 and 89 out of every 100 emails you send reach the reader’s inbox. An excellent score is 90% or higher

If you’re hitting this rate, it’s a good sign that your email marketing practices are working and that your messages are getting through to your audience.

Deliverability score

Deliverability rates lower than 95% may be a sign that you need to look a bit deeper into your email list quality, sender reputation, or the content you’re sending. Find and fix any issues, and you’ll be on the way to improving your overall email marketing performance. 

Keeping that number high does mean you’ll need to monitor and optimize your email marketing practices often. Spring clean your lists and segments, give your content a once-over, and double-check that your sending times align with best practices. 

Factors Affecting Email Deliverability 

Knowing what’s behind email deliverability helps you understand what to monitor and what changes to make to improve your chances of landing in the inbox. 

Sender Reputation 

Sender reputation is the score that email service providers (ESPs) assign to your email domain and IP address. It’s influenced by things like the number of emails sent, number of bounces, and number of spam complaints. The higher your reputation, the more likely your emails are to be delivered to the inbox. 

Quick Tips For Improving Sender Reputation: 

  • Consistent Sending Practices: Send emails at regular intervals. Sudden spikes in volume or iming changes could be seen as suspicious. 
  • Engagement Rates: Sending relevant content that offers value to your readers and ask for engagement. Reply, click, let us know, etc. 
  • Low Bounce Rates: Be ruthless in getting rid of invalid addresses in your email list. If you aren’t sending to invalid addresses, your bounce rate will drop. 

Email Authentication Protocols 

Email authentication protocols are rules that domain name system (DNS) records follow for verifying that your emails are coming from a real, trustworthy source. Set these up early and properly, and it can make a huge difference to your email deliverability score. 

Functions of SPF, DKIM, and DMARC: 

  • SPF: Specifies which mail servers can send emails on behalf of your domain. This helps prevent unauthorized senders from spoofing your domain. 
  • DKIM: Add a digital signature to your emails to verify they haven’t been altered. 
  • DMARC: Provide a mechanism for email receivers to report back on authentication results. It also instructs receiving servers on how to handle emails that fail SPF or DKIM checks.

Spam Filters 

Spam filters are email marketers’ least favorite things in the world. ESPs use these automated tools to detect and block unwanted emails. They analyze your subject lines, content, and sender information. If these filters flag something on one of your emails, they could send you right to spam. 

Best Practices: 

  • Balanced Content: Use a good text-to-image ratio so your emails look professional. 
  • Avoid Spammy Language: Stay away from words and phrases usually flagged as spam, in subject lines and the email body. 
  • Proper Formatting: Make sure you’re using clean HTML code and your links work. 

Email Content and Design 

Yes, the content and design of your emails can also affect deliverability. Emails that are well-designed, easy to read, and relevant to the reader are more likely to get to the inbox. Poor design, broken links, or irrelevant content can trigger spam filters and you know what happens then! 

Tips for Email Design: 

  • Mobile-Friendly: Double-check that your emails are responsive and look good on all devices. 
  • Engaging Content: Provide real value and relevance to your audience. What would they want to see? 
  • Clear Call-to-Action: Make it easy for your reader to understand exactly what you want them to do. 

Recipient Engagement 

This is all about how people interact with your emails. High engagement rates, like opens, clicks, and replies, show ESPs that your emails are valuable and relevant. Low engagement rates make ESPs think nobody’s interested and they’ll dampen down your deliverability. 

Improving Engagement: 

  • Personalization: Tailor emails to specific recipient preferences and behaviors. This will encourage interest and engagement. Data is key here! 
  • Segmentation: Target specific groups within your email list based on their interests and actions so you know they’re getting relevant content. 
  • Interactive Content: Use engaging elements like polls, quizzes, and personalized offers to entice clicks. 

Why Conduct an Email Deliverability Audit? 

An email deliverability audit helps you find and fix issues that stop your emails from reaching your audience’s inbox. Regular audits help you uncover problems and figure out how to fix them so you can keep finding those inboxes! 

Identifying Deliverability Issues 

You can’t fix something you don’t know is a problem! Auditing your account will show up all the things that might be making your deliverability worse. These often include: 

  • High Bounce Rates: Indicates problems with email list quality. 
  • Spam Complaints: Suggests issues with content relevance or frequency. 
  • Low Engagement: Points to the need for better targeting or more engaging content. 

Improving Sender Reputation 

Your reputation precedes you… So make sure it’s a good one. Fix the issues, and your sender reputation will tick up a few inbox-friendly notches. 

  • Tracking Key Metrics: Track and analyze key performance indicators to see where you can do better. 
  • Using Feedback Loops: Study ESP feedback to understand complaints. Understanding means you can find ways to fix it. 
  • Following Best Practices: Follow industry standards for email marketing. They’re there for a reason! 

Enhancing Audience Engagement 

Customers not super engaged? An audit might turn up some interesting data as to why. Try things like: 

  • Re-Engagement Campaigns: Target inactive subscribers with special offers or surveys just for them. 
  • Content Testing: A/B test different email formats and content types to see what your audience prefers (and stop doing what they don’t like). 
  • Personalized Offers: Use recipient data to give them specific recommendations based on their likes or history.


  1. Deliverability strategies vary significantly across different countries, which is essential for optimizing email campaigns.
  2. In the US and the UK, providers mainly focus on user engagement when scoring senders. They look at how users interact with emails, such as opening, clicking, and purchasing. Therefore, the strategy should emphasize sending emails to engaged segments and avoiding full list sends.
  3. In Germany, the key factor is infrastructure. Providers like T-Online prioritize the alignment of the sender’s infrastructure, requiring a dedicated IP and sending domain. The list must be double opt-in, and maintaining a clean list is critical. Strict rules govern who you send to, what you send, and how you send it.
  4. In France, the primary focus is on the email content. The three main providers (Free, Orange, and SFR) have distinct filtering mechanisms. Free blocks IPs for an hour if the content appears spammy and increases the block time with continued sending. Orange and SFR use the Vade filter, which analyzes the content of emails and the history of sends. If the filter is triggered, the message is blocked. To avoid this, it’s crucial to avoid sending repetitive content, change subject lines and templates frequently, and personalize emails as much as possible.
  5. Across all markets, it is important to prioritize sending to engaged segments and ensure that content is personalized and not repetitive. However, different markets prioritize these aspects differently, so tailoring your strategy to each specific market is key.

Step-By-Step Guide to Email Deliverability Audit in Klaviyo 

Here’s how to do a comprehensive email deliverability audit of your Klaviyo account. 

Step 1: Review Sending Domains and DNS Settings

Log into your Klaviyo account using your credentials. 

Verify Sending Domains: 

  • Go to “Settings” > “Email” > “Domains”. 
  • Make sure that your sending domains are verified. 
  • If not, follow the prompts to verify your domain.
Sending domain

Check DNS Settings: 

  • Use tools like MXToolbox to verify SPF, DKIM, and DMARC settings. 
  • For SPF, enter your domain in the MXToolbox SPF lookup tool. 
  • For DKIM, ensure you have added the DKIM records provided by Klaviyo to your DNS settings. 
  • For DMARC, create a DMARC record in your DNS settings, specifying your policy. 

Step 2: Analyze Email List Health 

Go to “Lists & Segments” in your Klaviyo dashboard. 

Identify Inactive Subscribers: 

  • Create a segment for users who haven’t engaged in the last 6 to 12 months. 
  • Go to “Create List/Segment” > “Segment” and set the criteria for inactivity. 

Send Re-Engagement Campaigns: 

  • Create a re-engagement email campaign targeting the inactive segment. 
  • If subscribers don’t engage, remove them from your list to maintain list health. 

Remove Invalid Addresses:

  • Regularly check for and remove hard bounces and unsubscribes from your list. 
  • Go to “Profiles” and filter it by your “Bounced” or “Unsubscribed” segments. 

Step 3: Evaluate Email Content and Design 

Review your most recent campaigns and analyze them carefully. Bad content and unappealing design could be causing people to bounce sooner than they would otherwise. 

Review Recent Campaigns: 

  • Go to “Campaigns” and select recent campaigns. 
  • Check your open rates, click rates, and bounce rates for each one. 
  • If they consistently fall short, it’s a sign that something needs changing. 

Optimize Subject Lines and Content:  

  • Analyze your subject lines to make sure they’re clear, concise, and not spammy. 
  • Make sure your content is personalized and has a balanced text-to-image ratio. 

Check Mobile Optimization: 

  • Use the email preview feature to check if your emails are mobile-friendly. 
  • Make changes to the layout if you need to.

Step 4: Monitor Engagement Metrics 

Access Campaign Reports: Go to “Analytics” > “Metrics”. 

Review Campaign Metrics 

  • Review things like open rates, click-through rates, and bounce rates. 

Identify Low-Engagement Segments 

  • Create segments based on engagement levels.
  • Go to “Lists & Segments” > “Create List/Segment” > “Segment” and set the criteria you want for low engagement.

Implement Re-Engagement Strategies 

  • Send careful re-engagement emails to these groups to try and get them to interact. 
  • Offer incentives or special content with the aim of getting the click. 

Step 5: Examine Email Sending Practices 

Keeping on track with the industry best practices will help keep your emails in the inbox because they’re behaving just as ESPs expect them to. Nothing suspicious or weird. 

Check Sending Frequency: 

  • Go to “Campaigns” and check how often you’re sending emails. 
  • Make sure you aren’t overwhelming your subscribers with too many. 

Conduct A/B Testing:

  • Create A/B tests for send times to see what works best. 
  • Go to “Campaigns” > “Create Campaign” > “Email.” 
  • Create your first campaign then click on “Create A/B Test” at the bottom. 
  • Set different send times for each version. 

Use Send Time Optimization: 

  • Go to “Campaigns” > “Options” > “View Smart Send Time Report.” 
  • Click on “Create New Test” and follow the prompts to find the perfect send times. 
  • Enable Smart Sending so your emails will always arrive at a good time for the receiver. 

Step 6: Check Compliance with Regulations 

Some regulations apply everywhere, and some apply in certain regions. Do your research beforehand so you know what you’re supposed to be complying with. 

Verify Consent Collection: 

  • Use a double opt-in for new subscribers so you KNOW they’re in for real. 
  • Go to “Signup Forms” and enable double opt-in for all forms. 

Review Unsubscribe Options:

  • Make sure every email includes an easy-to-find unsubscribe link. 
  • Get a few people to test the unsubscribe process so you know it’s user-friendly. 

Update Privacy Policies:

  • Regularly review and update your privacy policies. 
  • If you make changes, send a quick email to let your subscribers know. 

Using Klaviyo Features for Improved Deliverability 

Klaviyo offers some handy tools to boost email deliverability. Using them smartly and they can help your emails reach the inbox and engage your audience. 

  • Deliverability Reports: Track open rates, click-through rates, bounce rates, and spam complaints to identify issues ASAP. 
  • Email Health Dashboard: Get a helpful overview of your sender reputation and deliverability trends so you keep your reputation up. 
  • Smart Sending: Manage your email frequency with your readers in mind, to prevent over-sending and lower spam complaint numbers. 
  • Segmentation and Personalization: Target specific groups and personalize each one’s content to get some engagement going. 
  • Automated Workflows: Create email sequences based on user behavior for emails that are right on time and speak to your people. 

Using Third-Party Email Deliverability Test Tools 

Klaviyo provides valuable insights and tools. But don’t discount using third-party email deliverability test tools for different perspectives and ideas: 

  • This is a specialized technology giving you the highest possible level of granularity when it comes to deliverability statistics. It is our top recommendation for brands who’re sending 3M+ emails monthly.
  • This free tool analyzes your email for possible spam triggers and gives you a detailed report with a spam score.
  • GlockApps: A platform offering in-depth analysis, inbox placement tests, spam filter monitoring, and more good stuff.
  • MXToolbox: Provides tools for verifying email server configurations, checking DNS records, and finding possible blacklisting issues before they hit you. 

YOCTO’s Klaviyo Audit Services: Elevate Your Email Marketing 

YOCTO’s Klaviyo audit services are designed to fine-tune your email marketing strategy. Our audits delve deep into your Klaviyo account, making sure every part of it is operating at its peak. 

Our services include: 

  • Data Analysis: We examine historical data to spot trends and growth opportunities for your business. 
  • Deliverability Audit: We assess your email deliverability and make changes so your emails go to the inbox, not the spam folder. 
  • Sign-Up Paths Audit: We review all your sign-up paths, streamlining your lead capture and making sure your subscriber list is high quality. 
  • Flow Automation Audit: We give your email flows the once-over to make sure they’re bringing in leads and converting. 
  • Lists & Segments Audit: We analyze your lists and segments so they’re clean, well-organized, and precisely targeted. 
  • Campaigns Audit: We do a deep dive of your email campaigns for engagement, design, and content effectiveness. Plus, we’ll give you actionable insights to make them even better. 

Why Choose YOCTO, a Klaviyo Master Platinum Partner? 

By partnering with YOCTO, a Klaviyo Master Platinum Partner, you place your email marketing strategy in the hands of seasoned professionals. Here’s what sets us apart:

  • Industry Recognition: Independently recognized by Klaviyo as a top agency in the USA and Europe, we bring a wealth of experience and expertise to your audits.
  • Proven Success: Our methods consistently deliver results. No more guesswork— we provide a clear path to nailing your revenue and retention goals. 
  • Experience with Leading Brands: We’ve partnered with some of the world’s most renowned brands, such as Tesonet, as well as rapidly growing startups like Miracare. Our diverse experience across industries and business sizes means we can provide tailored solutions that really work. 

YOCTO’s Klaviyo Audit Process: Thorough and Insightful 

We don’t do half a job. We’ll audit your account in detail and give you understandable feedback, as well as actions you can take to improve things. 

  1. Discovery Call: We begin with a free, no-obligation discovery call to give us a better idea of your brand and your specific needs. 
  2. Comprehensive Audit: We’ll conduct a deep dive of your Klaviyo account, looking at data performance, deliverability, sign-up paths, flow automation, lists and segments, campaigns, and experimentation maturity. 
  3. Detailed Report: You’ll receive an info-packed report highlighting areas for improvement, including actionable recommendations customized to your brand. 

Ready to elevate your email marketing? Book your discovery call today and let’s see how we can help you achieve superior email deliverability and an increased ROI.

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