Struggling with poor open rates or emails landing in spam? Klaviyo deliverability is the key to ensuring your campaigns reach the right inboxes — and get read.
Email marketing success isn’t just about crafting the perfect subject line or designing stunning templates. If your messages never make it past spam filters, your ROI suffers. The good news? With the right strategies, you can improve Klaviyo deliverability and secure more inbox wins.
In this guide, we’ll cover 11 proven fixes that help brands strengthen their sender reputation, optimize engagement, and maximize email performance in 2025.
Why Klaviyo Deliverability Matters
Deliverability is the lifeline of email marketing. For ecommerce brands using Klaviyo, it doesn’t matter how beautifully designed or well-segmented your emails are—if they don’t land in the inbox, they don’t generate revenue. In 2025, inbox placement is not just about avoiding the spam folder, it’s about ensuring every message builds trust and strengthens your brand’s reputation.
Inbox placement vs spam folder
The difference between your email appearing in the primary inbox versus the spam folder can be the difference between a sale and a lost customer. Studies show that emails landing in the spam folder receive 90% fewer opens, which means your marketing investment instantly goes to waste. Internet Service Providers (ISPs) like Gmail, Outlook, and Yahoo now evaluate sender behavior more closely than ever, factoring in engagement signals, complaint rates, and authentication protocols to decide whether to deliver your emails to the inbox.
For Klaviyo users, this means deliverability is not just a technical requirement—it’s a competitive advantage. Brands that consistently land in the inbox drive higher engagement, stronger customer loyalty, and ultimately, more revenue.
The hidden cost of poor deliverability
Poor deliverability doesn’t just impact your current campaign—it creates a long-term drag on performance. If too many of your emails bounce, get ignored, or trigger spam complaints, your domain and IP reputation suffer. This lowers inbox placement across the board, even for your most engaged subscribers.
Hidden costs include:
- Lower revenue per send because fewer people even see your offers.
- Increased ad spend as you rely on paid channels to replace lost email revenue.
- Damaged brand trust when customers never receive order updates, promotions, or loyalty perks.
For ecommerce, where repeat purchases and customer lifetime value are critical, these hidden costs add up quickly. A brand with 100,000 subscribers could be losing tens of thousands of dollars per month simply because deliverability issues prevent customers from seeing their emails.
Impact on revenue and brand reputation
Email remains one of the highest ROI channels for ecommerce, generating on average $36 for every $1 spent. But this ROI assumes high inbox placement. If your deliverability rate drops from 95% to 75%, that’s a 20% loss of visibility, which could translate into hundreds of thousands in lost sales annually.
Beyond numbers, deliverability directly affects your brand reputation. If customers don’t receive important messages like shipping confirmations or password resets, they lose trust in your reliability. Worse, if your emails consistently land in spam, customers may assume your brand is untrustworthy or irrelevant.
In 2025, inbox placement is no longer a back-end technical detail—it’s a frontline business priority. Brands that prioritize Klaviyo deliverability don’t just send more emails, they create stronger, more profitable customer relationships.
“Strong deliverability is the heartbeat of every successful Klaviyo campaign — without inbox wins, even the best content goes unseen.”
Common Klaviyo Deliverability Challenges
Even with Klaviyo’s advanced features, ecommerce brands often run into deliverability roadblocks. These challenges usually stem from list quality, engagement signals, and technical setups. Understanding the most common issues is the first step toward fixing them.
High bounce rates
A bounce happens when your email cannot be delivered to a recipient’s inbox. There are two types:
- Hard bounces: Permanent issues, like invalid or fake email addresses.
- Soft bounces: Temporary issues, such as full inboxes or server problems.
High bounce rates send a red flag to Internet Service Providers (ISPs), lowering your sender reputation. For ecommerce, this often happens when lists aren’t cleaned regularly, or when emails are collected through low-quality sources like giveaways or purchased lists.
Pro tip: A healthy bounce rate in Klaviyo should stay below 2%. Anything higher signals urgent list hygiene problems.
Spam complaints
Spam complaints occur when recipients mark your message as spam or junk. Even a small number of complaints can have an outsized effect on your sender reputation. ISPs use complaints as a key indicator of whether your emails are wanted.
For Klaviyo users, spam complaints often spike when:
- Emails are sent too frequently.
- Content feels irrelevant or overly promotional.
- Subscribers never gave proper consent in the first place.
Keeping complaint rates below 0.1% per campaign is crucial to maintaining deliverability.
Low engagement signals
In 2025, ISPs prioritize engagement more heavily than ever. Open rates, click-through rates, and time spent reading are all monitored. If subscribers consistently ignore your messages, ISPs assume your content isn’t valuable, pushing future emails toward the spam folder.
Warning signs in Klaviyo:
- Open rates below industry benchmarks: (20–25%).
- Declining click-through rates over several months.
- Rising unsubscribe rates.
Low engagement doesn’t just hurt deliverability—it’s a sign that your strategy needs more personalization and segmentation.
Domain or IP reputation issues
Your domain and IP act like your sender “ID card.” If either develops a poor reputation, your emails will struggle to reach inboxes, no matter how good your content is.
Common causes of reputation damage:
- Sending high volumes too quickly without warming up.
- Emailing large numbers of unengaged or inactive subscribers.
- Sudden spikes in complaints or bounces.
Klaviyo provides deliverability reporting tools to monitor these issues, but it’s up to you to maintain sending practices that build long-term trust with ISPs.
11 Fixes for Klaviyo Deliverability
The good news about deliverability is that almost every issue can be fixed. Klaviyo provides the tools you need, but success depends on consistent best practices. Below are 11 proven strategies to keep your emails landing in inboxes—not spam folders—in 2025.
Authenticate your domain (SPF, DKIM, DMARC)
Domain authentication is the foundation of email trust. By setting up SPF, DKIM, and DMARC records in your DNS, you prove to ISPs that your emails are legitimate and not spoofed. Without authentication, inbox providers are far more likely to reject or filter your emails.
Steps:
- Add SPF and DKIM records for your domain.
- Implement DMARC for reporting and enforcement.
- Test using tools like Google Postmaster or Klaviyo’s deliverability reports.
👉 Authentication is non-negotiable—it’s the first step every ecommerce brand should take.
Use a dedicated sending domain
Instead of sending from Klaviyo’s shared servers, set up a dedicated sending domain. This gives you complete control over your sender reputation. With a dedicated domain, your deliverability won’t be affected by other brands’ practices.
Pro tip: Use a subdomain like mail.yourstore.com for marketing while keeping your main domain (yourstore.com) for transactional emails.
Warm up new sending infrastructure
If you suddenly send 100,000 emails from a brand-new domain or IP, ISPs will see it as suspicious. Instead, “warm up” your sending infrastructure by gradually increasing send volumes over 2–4 weeks.
Example:
- Week 1: Send to 10–15% of your most engaged subscribers.
- Week 2: Increase to 25–30%.
- Week 3–4: Expand to full list, but prioritize active segments.
This gradual approach helps build a strong sender reputation from the start.
Maintain a healthy email list (clean regularly)
Email list hygiene is one of the most powerful deliverability boosters. Regularly remove:
- Invalid or bouncing addresses.
- Subscribers who haven’t opened in 6–12 months.
- Spam traps and role-based emails (like info@, sales@).
Klaviyo makes this easier with smart segments that automatically filter unengaged profiles.
Segment engaged vs unengaged subscribers
Not every subscriber should receive every email. By segmenting, you increase engagement rates and reduce complaints.
Engaged segments might include:
- Opened or clicked in the last 90 days.
- Made a purchase in the last 6 months.
- Added to cart but didn’t check out.
Focusing campaigns on these groups boosts open rates and tells ISPs that your emails are valuable.
Optimize subject lines for deliverability
Your subject line is the first thing subscribers see—and ISPs also scan it for spammy signals. Avoid:
- Excessive use of caps or exclamation marks.
- Overhyped phrases like “100% FREE” or “LIMITED TIME ONLY.”
- Misleading copy that triggers spam complaints.
Instead, write clear, curiosity-driven subject lines that encourage genuine opens. Example:
❌ “GET THIS NOW OR MISS OUT!!!”
✅ “A little surprise for your next order 🎁”
Personalize content to boost engagement
Personalized emails consistently outperform generic blasts. Klaviyo makes personalization easy with:
- First name and location targeting.
- Dynamic product recommendations.
- Behavioral triggers (cart, browse, or purchase history).
Higher engagement (opens, clicks, conversions) sends strong positive signals to ISPs, improving inbox placement.
Balance text-to-image ratio
Emails that are too image-heavy often get flagged as promotional or spam. A good balance is 60% text and 40% images. Always include alt text for images so subscribers (and ISPs) can interpret your content even if images don’t load.
Monitor email frequency and cadence
Over-sending is one of the top causes of unsubscribes and complaints. At the same time, under-sending can cause disengagement.
Best practice for ecommerce in 2025:
- 2–3 campaigns per week for active subscribers.
- Automated flows for high-intent actions (cart abandonment, post-purchase).
- Preference centers so subscribers control frequency themselves.
Track sender reputation and blacklist status
Your sender reputation is like a credit score. Monitor it regularly to ensure no hidden issues are tanking deliverability.
Tools to use:
- Google Postmaster Tools.
- Klaviyo’s deliverability reports.
- Third-party blacklist monitors.
Catching issues early allows you to adjust before inbox placement is severely impacted.
Leverage Klaviyo deliverability tools and reporting
Klaviyo provides built-in dashboards for bounce rates, spam complaints, and engagement trends. Use these reports weekly to identify red flags before they escalate. Combine them with third-party monitoring for a complete deliverability picture.
Advanced Deliverability Tips for 2025
Email deliverability in 2025 is more sophisticated than ever. ISPs now use AI-driven algorithms, visual branding standards, and engagement signals that go beyond traditional metrics. For ecommerce brands using Klaviyo, staying ahead requires embracing new strategies that align with how inbox providers evaluate trust and relevance today.
AI-driven engagement predictions
Artificial Intelligence is reshaping email marketing. Platforms like Klaviyo now use predictive analytics to forecast subscriber behavior, such as:
- Who is likely to open an email.
- Who is at risk of unsubscribing.
- Who is ready to make a purchase.
By sending the right message to the right person at the right time, you avoid blasting your entire list and instead focus on high-probability conversions. This not only improves ROI but also sends strong deliverability signals to inbox providers.
- In practice: If Klaviyo predicts that 30% of your audience is likely to purchase within the next 14 days, build a segment around that group and target them with exclusive offers.
BIMI (Brand Indicators for Message Identification) adoption
BIMI is quickly becoming a deliverability game-changer. It allows brands to display their verified logo next to their emails in supported inboxes like Gmail and Yahoo.
Why it matters:
- Increases brand trust and recognition.
- Boosts open rates by making your emails stand out visually.
- Signals to ISPs that your brand is authenticated and reputable.
To implement BIMI, you’ll need:
- A verified domain with DMARC enforcement.
- An SVG version of your logo.
- A VMC (Verified Mark Certificate) issued by an authorized provider.
While BIMI requires upfront effort, the payoff in visibility and trust is substantial.
Integrating SMS to support email campaigns
Inbox algorithms value subscriber engagement across channels, not just within email. When you combine Klaviyo SMS with email, you strengthen overall deliverability by:
- Diversifying communication touchpoints.
- Reducing reliance on a single channel.
- Reinforcing important messages (e.g., flash sales, shipping updates).
Example workflow:
- Day 1: Abandoned cart email.
- Day 2: SMS reminder with a limited-time discount.
- Day 3: Final email nudge with social proof.
This coordinated approach increases conversions while lowering the risk of email fatigue.
Best Practices for Ongoing Success
Deliverability is not something you fix once and forget. Inbox algorithms constantly evolve, subscriber preferences shift, and even the smallest missteps can harm your sender reputation. To ensure long-term Klaviyo deliverability success in 2025, brands need a proactive approach that combines monitoring, optimization, and trust-building.
Regular audits of your sending practices
Performing deliverability audits at least once per quarter helps you catch issues before they escalate. Key elements to review include:
- Bounce rates and complaint rates.
- Engagement levels across segments.
- Authentication records (SPF, DKIM, DMARC).
- Blacklist status and sender reputation.
- Pro tip: Document your audit results to identify trends over time. A rising bounce rate, even if small, can be an early warning sign.
Continuous testing and optimization
Inbox providers reward senders who consistently deliver relevant, engaging content. That means every email campaign should be treated as a test.
What to test regularly:
- Subject lines (curiosity vs. clarity).
- Send times (morning vs. evening, weekday vs. weekend).
- Content balance (offers, education, storytelling).
- Calls-to-action (buttons vs. text links).
By applying A/B testing in Klaviyo, you can quickly determine what resonates with your audience and improve both engagement and deliverability.
Building long-term trust with subscribers
Deliverability ultimately boils down to trust. If subscribers open, click, and interact with your emails, ISPs see you as a reliable sender. If they ignore, unsubscribe, or complain, you’ll slide into spam.
Ways to strengthen subscriber trust include:
- Transparent sign-up processes (clearly state what they’ll receive and how often).
- Preference centers so users can control frequency and content type.
- Consistent branding and voice that reassures subscribers your emails are authentic.
- Valuable content beyond promotions—guides, product tips, or exclusive insights.
- Think of email as: a relationship, not just a sales channel. Respect subscriber expectations, and they’ll reward you with engagement that keeps your deliverability strong.
Shocking Truth: Why Poor Deliverability Quietly Destroys Ecommerce Revenue
Email deliverability isn’t just a technical issue—it’s a silent revenue killer. Many ecommerce brands assume that if they “send an email, it gets delivered.” The reality is very different. Inbox placement, engagement signals, and reputation management directly determine whether customers even see your campaigns.
Case Study: From Lost Revenue to Inbox Success
Situation:
A mid-sized Shopify apparel brand was investing heavily in Klaviyo campaigns—sending weekly promotions, abandoned cart flows, and product launches.
Problem:
Despite consistent effort, sales from email were declining. Klaviyo dashboards showed good open rates, but revenue per campaign was shrinking. Upon investigation, they discovered 40% of their emails were landing in spam folders across Gmail and Yahoo.
Steps Taken:
- Authenticated their domain with SPF, DKIM, and DMARC.
- Cleaned their email list, removing 15% of inactive subscribers.
- Segmented audiences to target only engaged customers first.
- Gradually warmed up a dedicated sending domain.
- Optimized subject lines and reduced overuse of promotional keywords.
Results:
Within 60 days, their inbox placement improved from 62% to 93%. Email-attributed revenue increased by 48%, and customer complaints dropped significantly.
Data: The Real Cost of Poor Deliverability
According to Validity’s 2025 Email Deliverability Benchmark Report:
- Average inbox placement for ecommerce brands sits at 84%, meaning 16% of emails never reach customers.
- Every 1% improvement in inbox placement can increase revenue by up to 4% for high-volume senders.
- 70% of consumers say if a brand’s emails always go to spam, they’re more likely to unsubscribe permanently.
This data shows that deliverability is not a minor detail—it directly impacts revenue, retention, and long-term brand perception.
Perspective: Perception vs Reality
What people think:
Many ecommerce owners believe deliverability is only about avoiding spammy subject lines or sending fewer emails.
Reality:
Deliverability is a complex ecosystem that involves domain reputation, authentication, engagement signals, list hygiene, and ISP algorithms. Sending fewer emails won’t solve the problem if your infrastructure and practices are flawed.
Explanation:
ISPs evaluate sender trust holistically. If you fail to authenticate your domain, ignore list cleaning, or keep emailing inactive subscribers, your emails will continue to land in spam—even if your content looks “normal.”
Summary & Implications
This case study and supporting data reveal a critical insight: poor deliverability is the hidden leak in ecommerce revenue pipelines. Brands often chase new acquisition channels while ignoring the fact that up to 20% of their email reach may be wasted.
Tips for brands:
- Audit your deliverability quarterly.
- Track inbox placement, not just open rates.
- Treat authentication and list hygiene as ongoing processes, not one-time tasks.
The implication is clear—brands that master Klaviyo deliverability in 2025 will not only recover lost revenue but also build stronger trust with customers who actually receive and engage with their emails.
FAQs
Before diving into the technical review, let’s address some of the most common questions ecommerce brands ask about Klaviyo deliverability. These answers will help clarify misconceptions and provide actionable insights.
The fastest way to fix spam issues is to authenticate your domain (SPF, DKIM, DMARC), clean your email list regularly, and avoid spam-triggering subject lines or content. Start by sending only to engaged subscribers, then gradually expand as deliverability improves. Setting up a dedicated sending domain also gives you more control over your reputation.
A strong deliverability rate for ecommerce brands is typically above 90% inbox placement. Anything below 85% indicates problems with sender reputation, list hygiene, or engagement. Keep in mind that “delivery rate” (emails accepted by the ISP) is not the same as “inbox placement” (emails reaching the inbox vs spam).
Yes, authentication is one of the most important deliverability fixes. Setting up SPF, DKIM, and DMARC tells inbox providers your emails are legitimate and secure. Without authentication, your emails are much more likely to be filtered as spam—even if your content is high quality.
It’s best practice to clean your list every 30 to 60 days, depending on your sending volume. Remove invalid addresses, bounces, and unengaged subscribers who haven’t opened in 6–12 months. Regular cleaning improves engagement rates, which directly boosts deliverability.
The biggest factors are:
- Domain authentication and sender reputation.
- Engagement signals (opens, clicks, replies).
- List hygiene and segmentation.
- Content quality (avoiding spammy language and poor formatting).
- Sending frequency and cadence.
Ultimately, inbox placement is determined by how trustworthy and relevant your emails appear to ISPs. The more engaged your audience, the stronger your deliverability will be.
Review Section
After working with dozens of ecommerce brands, it’s clear that Klaviyo deliverability fixes can completely transform email performance. Small technical improvements often lead to significant increases in revenue, engagement, and subscriber trust. Below are my detailed reviews of the most impactful strategies.
Domain Authentication: ★★★★★
Review: Setting up SPF, DKIM, and DMARC is the single most important step for deliverability success. Once authentication is in place, inbox providers immediately recognize your emails as trustworthy. In practice, brands see a 10–20% boost in inbox placement within weeks. Think of it as the foundation of all future email performance.
List Hygiene: ★★★★★
Review: Regularly removing unengaged or invalid subscribers is like pruning a tree—it strengthens overall health. When lists are cleaned every 30–60 days, open and click rates improve, spam complaints drop, and deliverability stabilizes. Ecommerce brands that clean lists quarterly report 15–25% higher engagement rates.
Segmentation: ★★★★★
Review: One of Klaviyo’s strongest features is advanced segmentation. By sending only to engaged audiences, you lower spam complaints and signal to ISPs that your content is relevant. Segmenting by behavior (purchasers, cart abandoners, browsers) often results in 2–3x higher open rates compared to generic blasts.
Content Optimization: ★★★★★
Review: The way you design and write your emails has a direct impact on inbox placement. Balancing text and images, avoiding spammy keywords, and personalizing content makes emails look natural and engaging. When brands shift to value-driven subject lines and storytelling, both deliverability and conversion rates rise.
Reputation Monitoring: ★★★★★
Review: Even if your setup is perfect, deliverability can slip if you don’t monitor it. Tools like Google Postmaster and Klaviyo reporting help brands catch red flags early, such as blacklist issues or sudden bounce spikes. Monitoring reputation weekly ensures problems are fixed before they impact revenue.
Final Verdict
Klaviyo deliverability isn’t just about technical fixes—it’s about creating a trustworthy, consistent, and engaging email experience. When brands combine domain authentication, list hygiene, segmentation, optimized content, and monitoring, they unlock the full revenue potential of their email channel.
Conclusion
Klaviyo deliverability matters because it directly impacts revenue, brand reputation, and customer trust. Without strong inbox placement, even the best-designed campaigns will fail to drive results.
The three main points to remember are:
- Technical foundation is key: Authentication, dedicated domains, and list hygiene set the stage for success.
- Engagement drives reputation: Segmentation, personalization, and optimized content signal value to inbox providers.
- Ongoing monitoring ensures growth: Regular audits, reputation tracking, and continuous testing keep deliverability strong in 2025.
Answer to the main question: Klaviyo deliverability is the hidden engine of email marketing performance—get it right, and you’ll maximize engagement, conversions, and customer loyalty.
Final tip: Don’t treat deliverability as a one-time fix. Build it into your marketing operations with quarterly audits, AI-driven segmentation, and a mix of email + SMS to diversify reach.
If this guide helped you understand how to improve Klaviyo deliverability, share this post with your team or fellow marketers—because every ecommerce brand deserves to have their emails land in the inbox where they belong.