8 Ways to Improve Newsletter Deliverability

Think of your newsletter as a package you’re sending to a subscriber. Your sender reputation is your return address, email authentication is the official postage, and your content is the package itself. If the return address looks suspicious or the package seems tampered with, the postal service—in this case, Gmail or Outlook—won't deliver it. This is deliverability in a nutshell: proving you’re a legitimate sender with valuable content. If you want to improve newsletter deliverability, you need to ensure every part of your "package" is in perfect order. This guide breaks down the process, step-by-step, so you can make sure your message always arrives safely in the inbox.

Key Takeaways

• Authenticate your domain before you do anything else: Setting up SPF, DKIM, and DMARC is a non-negotiable first step. This technical handshake proves you are who you say you are, building the essential trust needed to stay out of the spam folder.
• Focus on list quality, not just quantity: Your sender reputation is built on subscriber engagement. Keep your list healthy by using a double opt-in, regularly removing inactive subscribers, and making it easy to opt out. A smaller, engaged list is far more valuable than a large, dormant one.
• Treat deliverability as an ongoing practice: Your work isn't done after you hit send. Maintain a consistent sending schedule, create content that avoids spammy triggers, and regularly monitor your performance metrics to spot and fix issues before they become major problems.

What Is Newsletter Deliverability (and Why Does It Matter)?

You’ve spent hours crafting the perfect newsletter—the subject line is catchy, the content is compelling, and the call to action is crystal clear. You hit send, but what happens next? Does your email land in your subscriber’s primary inbox, get tucked away in the promotions tab, or disappear into the dreaded spam folder? This is the core of newsletter deliverability: ensuring your emails actually reach the people who signed up to receive them.

Think of it as the final, crucial step in your entire content process. If your newsletter isn't delivered to the inbox, your message is never seen, and all your hard work goes to waste. Poor deliverability means lower open rates, fewer clicks, and missed opportunities to connect with your audience. On the other hand, strong deliverability builds a foundation for a healthy, engaged subscriber base and a successful newsletter program. It’s not just a technical metric; it’s a direct reflection of your relationship with your audience and a key driver of your newsletter’s growth and profitability.

Delivery vs. Deliverability: What's the Difference?

It’s easy to mix up "delivery" and "deliverability," but they measure two very different things. Email delivery simply means that your email was successfully sent and accepted by the recipient's mail server. It’s a basic "message received" confirmation. You can have a 99% delivery rate and still have a major problem.

Deliverability, however, is about where your email lands after the server accepts it. Does it go to the main inbox where it’s likely to be seen, or does it get filtered into a spam or promotions folder? Excellent deliverability means your emails consistently arrive in the primary inbox, giving you the best possible chance of engaging your subscribers.

How Inbox Placement Affects Your Bottom Line

Simply put, if your emails don't reach the inbox, they can't generate results. Every newsletter sent to spam is a missed opportunity for clicks, conversions, and revenue. Poor inbox placement directly impacts your return on investment and can slowly erode the trust you’ve built with your audience.

Beyond the immediate financial impact, consistent inbox placement builds a positive feedback loop. When subscribers open and interact with your emails, they send positive signals to inbox providers like Gmail and Outlook. These providers learn that your content is valuable, which in turn helps improve future deliverability. High engagement proves your content is wanted, securing your spot in the inbox and protecting your long-term revenue stream.

What's Hurting Your Newsletter Deliverability?

Even the most beautifully crafted newsletter is useless if it lands in the spam folder. Several factors can prevent your emails from reaching the inbox, and understanding them is the first step to fixing the problem. From the words you use to your technical setup, every detail matters to inbox providers. Let's look at the four most common culprits that could be hurting your deliverability.

Spam Filters and Content Triggers

Think of spam filters as the first line of defense for an inbox. They scan incoming emails for red flags, and your content is a major part of that scan. Using spammy-sounding phrases (like "make money fast" or "act now!"), excessive punctuation, or all-caps subject lines can get you flagged. The same goes for the email's body. A good balance of text and images is important, as emails that are just one large image are often seen as suspicious. Ultimately, providing high-quality, relevant content is your best bet for getting past these filters and landing in the inbox where your subscribers can see it.

A Poor Sender Reputation

Your sender reputation is essentially a credit score for your email domain. Internet Service Providers (ISPs) like Gmail and Outlook use it to decide if you’re a trustworthy sender. This reputation is built over time based on how subscribers interact with your emails. High open and click-through rates tell ISPs that people want your content. On the other hand, high bounce rates, unsubscribe requests, and spam complaints will damage your score. How people react to your emails directly builds this reputation, making subscriber engagement one of the most critical factors for good deliverability.

Missing Email Authentication

Email authentication is a technical way of proving to ISPs that you are who you say you are. It’s like showing your ID at the door. Protocols like SPF, DKIM, and DMARC verify that your email is coming from an authorized server and hasn't been tampered with. Without proper authentication, your emails look suspicious, making it easy for spam filters to block them. Setting up these records tells providers like Gmail that you’re a legitimate sender, not a spammer or a phisher trying to impersonate your brand. This simple step is fundamental to building trust with email providers and is a non-negotiable for serious publishers.

Low-Quality Lists and Poor Engagement

Sending emails to people who don't want them is one of the fastest ways to ruin your sender reputation. An email list filled with inactive subscribers, invalid addresses, or people who never agreed to hear from you will lead to low engagement and high complaint rates. This signals to ISPs that your content isn't valuable. To avoid this, it's crucial to regularly remove inactive subscribers and use a double opt-in process to confirm new sign-ups. A clean, engaged list is the foundation of any successful newsletter program and is essential for maintaining strong deliverability over the long term.

How to Set Up Email Authentication

Think of email authentication as your newsletter’s official ID. It’s a set of technical standards that prove to inbox providers like Gmail and Outlook that your emails are legitimate and not sent by a spammer impersonating you. When you authenticate your domain, you’re essentially vouching for every email you send, which is a huge step toward building trust and a positive sender reputation. Without it, your carefully crafted newsletters have a much higher chance of being flagged as suspicious and landing in the spam folder, completely unseen by your audience.

Setting up authentication involves adding a few records to your domain’s DNS settings. While it might sound technical, it’s a one-time setup that pays off in the long run. Most email service providers, including Letterhead, provide clear, step-by-step guides to walk you through the process. Taking the time to get SPF, DKIM, and DMARC in place is one of the most effective things you can do to improve your deliverability. It’s the technical foundation that allows your great content to actually get seen. It tells the world’s inboxes that you’re a serious publisher who respects the channel and your subscribers, making them far more likely to place your messages right where they belong: the inbox.

Set Up Your SPF Record

An SPF (Sender Policy Framework) record is like a public guest list for your domain. It specifies exactly which mail servers are authorized to send emails on your behalf. When an email arrives, the recipient's server checks your SPF record to see if the sending server is on the list. If it is, the email passes the check. If not, it’s flagged as suspicious. This simple verification step is your first line of defense against spammers who might try to spoof your domain. By clearly defining who can send your emails, you make it much harder for bad actors to impersonate your brand and damage your reputation.

Configure Your DKIM Signature

If SPF is the guest list, DKIM (DomainKeys Identified Mail) is the tamper-proof seal on the envelope. It adds a unique digital signature to every email you send. This signature is linked to your domain and is verified by the recipient's email server using a public key stored in your DNS records. This process confirms two things: that the email actually came from your domain and that its content hasn't been altered along the way. A valid DKIM signature is a powerful signal of trust that tells inbox providers your message is authentic, which is a key factor in email deliverability best practices.

Implement a DMARC Policy

DMARC (Domain-based Message Authentication, Reporting, and Conformance) is the security guard that uses the SPF and DKIM information to decide what to do. It tells receiving email servers how to handle emails that fail either the SPF or DKIM checks. You can set a policy to have those emails monitored, sent to quarantine (the spam folder), or rejected outright. DMARC also provides valuable reports that give you insight into who is sending emails from your domain, helping you spot potential abuse. Implementing a DMARC policy is a critical step in protecting your brand from phishing and spoofing attacks and gaining full control over your email channel.

Connect Your Custom Domain

Sending your newsletter from a generic email address like @gmail.com or @yahoo.com can hurt your credibility. Using a custom email domain (e.g., newsletter@yourbrand.com) is essential for looking professional and building trust with both subscribers and inbox providers. A custom domain reinforces your brand identity and signals that you are a legitimate business. Emails sent from a recognized, authenticated domain are far more likely to be delivered to the inbox. It’s a foundational step that not only improves deliverability but also strengthens your brand’s presence with every send.

How to Build and Maintain a Strong Sender Reputation

Think of your sender reputation as a credit score for your email domain. Internet Service Providers (ISPs) like Gmail and Outlook use it to decide if you’re a trustworthy sender. A great reputation means your newsletters land in the inbox. A poor one gets you a one-way ticket to the spam folder. This score isn’t a one-and-done deal; it’s something you build and protect with every single send.

Your reputation is tied to your sending domain and IP address, and it’s influenced by several factors: how many people mark your emails as spam, how many of your emails bounce, and how engaged your subscribers are. If you consistently send high-quality content to an engaged list, ISPs will see you as a legitimate sender. But if you send to a list full of invalid addresses or people who don’t open your emails, your reputation will take a hit. Building a strong sender reputation is a long-term strategy that requires consistent, thoughtful practices. It’s the foundation of good deliverability, ensuring your hard work actually gets seen.

Use a Double Opt-In Process

The best way to start your relationship with a new subscriber on the right foot is with a double opt-in. This means that after someone signs up for your list, they receive an email asking them to confirm their subscription by clicking a link. It might seem like an extra step, but it’s incredibly valuable. Implementing a double opt-in process ensures you’re gathering genuine, interested contacts who actually want to hear from you. This simple confirmation weeds out typos, fake email addresses, and bots, which helps protect your sender reputation from the very beginning. It’s a classic case of quality over quantity.

Manage Bounces and Complaints

Bounces and spam complaints are direct, negative feedback to ISPs. A hard bounce means an email address is invalid, while a soft bounce indicates a temporary issue, like a full inbox. Spam complaints happen when a subscriber clicks the "mark as spam" button. To maintain a strong sender reputation, you have to keep your complaint rates low. If recipients frequently mark your emails as spam, it will seriously damage your deliverability. You should regularly clean your email list to remove addresses that hard bounce or generate complaints. Being proactive about list hygiene is essential for sustaining a positive reputation and showing ISPs you’re a responsible sender.

Monitor Engagement Metrics

ISPs pay close attention to how subscribers interact with your emails. Low open rates, a lack of clicks, and high unsubscribe rates are all signals that your content might not be relevant or wanted. Regularly monitoring your engagement metrics is vital. If you keep sending emails to people who never open them, you’re telling inbox providers that your content isn’t valuable, which can hurt your reputation. Removing inactive subscribers helps ensure that your emails reach those who are genuinely interested. This not only improves your deliverability but also gives you a more accurate picture of your newsletter's performance.

Choose a Reputable Email Service Provider

The platform you use to send your newsletters plays a huge role in your deliverability. Selecting a reputable email service provider (ESP) is critical for maintaining a strong sender reputation. A good ESP has a strong IP reputation and established relationships with ISPs, which can significantly improve your inbox placement. They also provide the infrastructure and tools you need to follow best practices, like managing bounces and setting up authentication. A platform like Letterhead, which is designed specifically for publishers, understands the nuances of deliverability and provides the governance and insights needed to protect your reputation as you scale.

How to Create Content That Reaches the Inbox

You’ve authenticated your domain and built a solid sender reputation, but the work doesn’t stop there. The actual content of your newsletter plays a massive role in whether you land in the inbox or the spam folder. Inbox providers like Gmail and Outlook have sophisticated filters that scan everything from your subject line to your image-to-text ratio to determine if your email is legitimate and valuable to the recipient.

Think of it this way: your content is a direct signal of your intent. Spammy-looking content sends a clear message that you might not be a trustworthy sender. This includes using deceptive subject lines, stuffing your email with images and little text, or making it difficult for people to unsubscribe. On the other hand, creating thoughtful, well-formatted, and relevant content shows inbox providers that you’re sending something your subscribers actually want to read. Focusing on a high-quality content experience isn’t just good for your readers; it’s a fundamental part of a strong deliverability strategy.

Write Subject Lines That Avoid Spam Filters

Your subject line is the first piece of content that both subscribers and spam filters analyze. A clear, honest subject line gets you past the initial gatekeeper and encourages opens. Keep it concise and descriptive, ideally under 50 characters, to ensure it displays properly on mobile devices. Avoid using all caps, excessive exclamation points, and common spam trigger words like “free,” “urgent,” or “winner.” Personalizing the subject line with a subscriber's name can also help it stand out as a legitimate email rather than a generic blast.

Find the Right Balance of Text and Images

An email that’s just one giant image is a major red flag for spam filters. Spammers often use this tactic to hide problematic text from filters, so inbox providers are naturally suspicious of image-heavy emails. A good guideline is to maintain a ratio of about 60% text to 40% images. This balance makes your email look more like a genuine piece of communication. Always include alt text for your images, too. It not only improves accessibility for your readers but also gives spam filters more text to read, helping them understand your content’s context.

Make It Easy to Unsubscribe

It might seem counterintuitive, but a clear and easy-to-find unsubscribe link is essential for good deliverability. If a subscriber can’t figure out how to opt out, they’re far more likely to just hit the spam button out of frustration. A spam complaint is significantly more damaging to your sender reputation than an unsubscribe. Including a visible unsubscribe link is also a legal requirement under regulations like the CAN-SPAM Act. Treat the unsubscribe process as a tool for list hygiene—it ensures only engaged readers remain on your list, which sends positive signals to inbox providers.

Always Optimize for Mobile

A huge portion of your audience will open your newsletter on a smartphone. If your email is difficult to read or interact with on a small screen, you risk frustrating your subscribers. A poor mobile experience can lead to low engagement, deletions, and even spam complaints—all of which harm your deliverability. Use a responsive email template that automatically adjusts to different screen sizes. Before you hit send, always test your email to see how it looks on a mobile device. Ensure your fonts are legible, images load correctly, and links are easy to tap.

How to Keep Your Email List Clean

A large subscriber list looks impressive, but it’s the quality, not the quantity, that truly matters for deliverability. Sending emails to invalid addresses or people who never open them can damage your sender reputation and signal to inbox providers that your content isn't wanted. A clean email list is your foundation for strong engagement and successful inbox placement. It ensures you’re reaching people who are genuinely interested in what you have to say. Think of it as regular maintenance for one of your most valuable assets.

Keeping your list clean involves more than just removing bounced emails. It’s about creating a community of engaged readers who look forward to your newsletters. When your engagement rates are high, inbox providers see you as a credible sender, which helps your emails land in the primary inbox instead of the spam folder. A healthy list also gives you clearer insights into what’s working, as your performance metrics aren’t skewed by inactive contacts. Here’s how to keep your list healthy and effective.

Use Email Verification Tools

Before you send a single email to a new list, run it through an email verification service. These tools act like a bouncer for your subscriber list, checking for typos, disposable email domains, and other invalid addresses that lead to hard bounces. A high bounce rate is a major red flag for internet service providers (ISPs) and can quickly land your emails in the spam folder. Using a service like ZeroBounce or Clearout removes these problematic addresses from the start, giving your campaigns a much better chance of reaching real inboxes. It’s a simple, proactive step that protects your sender reputation and saves you from deliverability headaches down the line.

Practice Regular List Hygiene

List cleaning isn't a one-time task; it's an ongoing process. Good list hygiene means regularly reviewing your subscribers and removing those who are no longer engaged. If someone hasn't opened or clicked on an email from you in six months to a year, they've likely gone cold. Keeping them on your list can drag down your open rates and signal to ISPs that your audience isn't interested. By periodically cleaning out inactive contacts, you maintain a list of genuinely engaged readers. This not only improves your deliverability but also gives you a more accurate picture of your campaign performance, as your metrics will reflect an active and interested audience.

Prune Inactive Subscribers

It can feel painful to delete subscribers you worked hard to get, but it’s one of the healthiest things you can do for your newsletter. Sending emails to people who never open them hurts your sender reputation. Why? Because low engagement tells inbox providers that your content isn’t relevant or valuable, making it more likely they’ll filter your future emails as spam. A smaller, highly engaged list is always better than a massive, dormant one. Regularly pruning inactive subscribers ensures your engagement metrics—like open and click rates—stay strong. These positive signals are crucial for proving your legitimacy to ISPs and securing your spot in the primary inbox.

Run Re-Engagement Campaigns

Before you permanently remove an inactive subscriber, give them one last chance to connect. A re-engagement campaign, also known as a win-back campaign, is designed to do just that. Send a targeted email asking if they still want to hear from you, perhaps with a compelling subject line like "Is this goodbye?" or "We miss you." You can also offer a special discount or ask for feedback on what kind of content they’d prefer to receive. This gives subscribers an easy way to confirm their interest. For those who still don't respond, you can confidently remove them, knowing you did your best to re-engage them.

Sending Practices to Maximize Inbox Placement

Once your content is polished and your list is clean, the final piece of the deliverability puzzle is your sending strategy. How and when you send your newsletters sends powerful signals to inbox providers like Gmail and Outlook. A sudden, massive email blast from an unknown sender looks suspicious, while a consistent, predictable pattern from a trusted source is more likely to be welcomed. Think of it as building a relationship with the inbox providers; you need to earn their trust over time.

For publishers and brands managing multiple newsletters, these sending practices are non-negotiable for protecting your sender reputation across your entire portfolio. A mistake on one newsletter can impact the deliverability of others sharing the same domain or IP. This means being thoughtful about your sending frequency, how you introduce a new sending domain, and the way you scale your volume as your audience grows. It’s not about finding a secret trick to bypass spam filters. Instead, it’s about demonstrating that you’re a legitimate, responsible sender who provides value to your subscribers. By adopting a few key sending practices, you can show inbox providers that your emails are wanted, which is the single most important factor in achieving high inbox placement.

Find Your Ideal Sending Cadence

Consistency is your best friend when it comes to sending newsletters. Inbox providers favor predictable sending patterns, so establishing a regular cadence—whether it’s daily, weekly, or bi-weekly—helps build trust. An erratic schedule with long periods of silence followed by a sudden burst of emails can look spammy. Find a rhythm that works for your team and your audience, and stick to it. This consistency helps mailbox providers recognize you as a legitimate sender. Part of maintaining a healthy cadence also involves regularly cleaning your email list to remove inactive subscribers. Sending to an engaged audience ensures your metrics stay strong and signals that your content is valued.

Warm Up New Domains and IPs

If you’re sending from a new domain or IP address, you can’t just send 50,000 emails on day one. You need to "warm up" your sending infrastructure first. This process involves starting with a small volume of emails sent to your most engaged subscribers and gradually increasing the amount over several weeks. This slow and steady approach allows you to build a positive sending reputation from scratch. A sudden spike in volume from a "cold" IP is a major red flag for spam filters. A proper IP warming strategy shows inbox providers that you're a legitimate sender, not a spammer trying to fly under the radar.

Increase Send Volume Gradually

The principle of gradual growth doesn’t stop after the initial warm-up period. Even with an established sending reputation, you should avoid abrupt, massive increases in your send volume. For instance, if your subscriber list doubles overnight after a successful campaign, don’t immediately double the number of emails you send. Instead, scale your volume methodically over a period of 30 to 60 days. This continued, gradual increase helps maintain the trust you’ve built with email providers. It proves that your list growth is organic and that you’re scaling your sending practices responsibly, which helps keep your deliverability rates high as your audience expands.

Segment Your Subscriber Base

Sending the same message to everyone on your list is a missed opportunity for engagement and a potential risk to your deliverability. When you segment your audience into smaller groups based on their interests, behavior, or demographics, you can send more relevant, personalized content. This targeted approach leads to higher open and click-through rates. Why does this matter for deliverability? High engagement is a powerful positive signal to inbox providers. It tells them that your subscribers want to receive your emails, making it more likely that your future campaigns will land directly in the inbox rather than the spam folder.

How to Monitor Your Deliverability Performance

You can’t improve what you don’t measure. Keeping a close eye on your newsletter’s performance is the only way to catch deliverability issues before they turn into major problems. Consistent monitoring helps you understand how inbox providers view your emails and gives you the data you need to protect your sender reputation. Think of it as a regular health check for your newsletter program. By tracking the right numbers and using the right tools, you can stay proactive and ensure your content consistently reaches your audience.

Know Which Metrics to Track

Start by focusing on the numbers that tell the real story of your deliverability. Key email deliverability metrics include your delivery rate, open rate, click-through rate (CTR), spam complaint rate, and unsubscribe rate. While high open and click rates are great, a rising spam complaint or unsubscribe rate is a clear warning sign. These negative signals tell inbox providers that your content isn't wanted, which can quickly damage your sender reputation. Tracking these metrics over time helps you establish a baseline, so you can spot trouble as soon as it starts.

Use Deliverability Monitoring Tools

Your email platform’s built-in analytics are a great starting point, but dedicated deliverability tools can offer deeper insights. These services help you watch your performance across different inbox providers and alert you to potential problems. For ongoing monitoring, you should aim for a bounce rate under 3% and a spam complaint rate below 0.1%. Tools like Unspam can help you get more specific with your goals and analyze performance in greater detail. This allows you to move from simply tracking numbers to actively managing your inbox placement.

Test Before You Send

One of the best ways to protect your deliverability is to test your campaigns before they go out to your entire list. Inbox placement testing involves sending your newsletter to a "seed list" of email addresses at various providers (like Gmail, Outlook, and Yahoo) to see where it lands—the inbox, the promotions tab, or the spam folder. This process helps you identify potential issues with your content, authentication, or reputation before a full send. Analyzing these deliverability-specific benchmarks gives you a chance to fix problems and maximize your inbox placement.

Check Your Blacklist Status

Email blacklists are real-time lists of IP addresses and domains that have been flagged for sending spam. Landing on one can be devastating for your deliverability, as many inbox providers use them to filter incoming mail. It’s crucial to regularly check your blacklist status using monitoring tools. If you find your domain or IP on a list, you need to act quickly to identify the cause—like a sudden spike in spam complaints or a compromised account—and follow the delisting process for that specific blacklist. Staying off these lists is fundamental to maintaining a healthy sending reputation.

How to Fix Deliverability Issues

Seeing your newsletter’s performance tank because of deliverability problems can be incredibly frustrating. You’ve spent time creating great content, only for it to get lost on its way to the inbox. The good news is that these issues are almost always fixable. It just requires a methodical approach to figure out what went wrong and a clear plan to get back in the good graces of inbox providers.

Think of it as rebuilding trust. Something in your sending practices likely sent a negative signal to Internet Service Providers (ISPs), and now you need to show them you’re a legitimate, responsible sender who provides value to your subscribers. This process involves three key stages: first, you’ll need to do some detective work to diagnose the core issue. Second, you’ll create a strategic plan to recover your sender reputation. Finally, you’ll learn how to work with your email provider to monitor your performance and maintain a healthy sending status for the long haul. Let’s walk through each step.

Identify the Root of the Problem

Before you can fix anything, you need to know exactly what’s broken. Start by digging into your email analytics to find the source of the trouble. A sudden spike in your bounce rate could mean your list quality has declined, while a jump in spam complaints indicates your content or targeting is off. If recipients mark your emails as spam, it directly harms your sender reputation.

Check to see if your domain or IP address has been blacklisted using a monitoring tool. This is a common reason for widespread delivery failures. You should also review your recent sending history. Did you just send a campaign to a massive, unengaged list? Sending to people who aren't interested is a surefire way to hurt your reputation. Pinpointing the "when" and "what" of the problem is the first critical step toward a solution.

Create a Plan to Recover Your Reputation

Once you’ve identified the likely cause, it’s time to build a recovery plan. If your reputation has taken a hit, you need to re-establish trust with ISPs. The key is to start slow. Don't send a huge campaign right away. Instead, begin by sending emails only to your most engaged subscribers—the people who have opened or clicked in the last 30 to 60 days. This generates positive signals and shows ISPs that people want your emails.

As you see positive results, you can gradually increase your sending volume. This is also the perfect time to implement a double opt-in process for all new subscribers. It ensures you’re building a list of genuinely interested contacts, which is one of the best long-term strategies for protecting your sender reputation and avoiding future issues.

Work with ISPs and Email Providers

You don’t have to solve deliverability issues on your own. Your email service provider (ESP) is a valuable partner in this process. Reputable platforms have teams dedicated to deliverability and can offer specific insights into your account. They can help you confirm that your email authentication (SPF, DKIM, and DMARC) is correctly configured, which is a foundational piece of a good sending reputation.

For ongoing health, keep a close eye on your metrics. Aim for a bounce rate under 2% and a spam complaint rate below 0.1%. If you see these numbers creeping up, you can act quickly before major damage is done. Your ESP provides the tools to track these metrics, so make it a habit to check your performance dashboard regularly. Consistent monitoring is the best way to stay ahead of problems.

Common Deliverability Mistakes to Avoid

Even the most well-crafted newsletter can end up in the spam folder if you’re making a few common mistakes. Getting your deliverability right is about building trust with inbox providers, and that means avoiding practices that make you look like a spammer. Think of it as digital etiquette—following the rules shows respect for your subscribers and the systems designed to protect them.

Sometimes, these missteps are unintentional. You might be focused on growing your list quickly or designing an eye-catching email, but certain tactics can backfire and damage your sender reputation. By understanding these common pitfalls, you can be proactive about protecting your deliverability and ensuring your hard work actually reaches your audience. Let’s walk through four of the most frequent mistakes and how you can steer clear of them.

Sending to an Unengaged List

It can be tempting to hold onto every single subscriber, but sending emails to a list full of inactive contacts is one of the fastest ways to hurt your deliverability. When a large portion of your audience isn't opening your emails, it signals to providers like Gmail and Outlook that your content isn't valuable. This can cause your sender reputation to drop, leading to more of your emails landing in spam.

The solution is to practice good list hygiene by regularly removing subscribers who haven't engaged in a while. To prevent this problem from the start, use a double opt-in process. Requiring new subscribers to confirm their email address ensures you’re building a list of people who genuinely want to hear from you, which leads to higher engagement from day one.

Using Spammy Language or Formatting

We’ve all seen emails that just feel like spam. They often rely on gimmicky tactics that are major red flags for spam filters. Avoid using all caps in your subject lines, adding excessive exclamation points, or using multiple different font colors and sizes. These formatting choices make your email look unprofessional and can trigger spam filters automatically.

The same goes for your content. Steer clear of using too many images with very little text, broken code, or link shorteners. Be mindful of your word choice, as certain spam trigger words related to urgency, finances, or exaggerated claims can get you flagged. Focus on creating clean, valuable, and professional-looking content that your audience will actually want to read.

Forgetting Email Authentication

Email authentication is a technical step, but it’s non-negotiable for good deliverability. Protocols like SPF, DKIM, and DMARC are how you prove to inbox providers that you are who you say you are. Without them, there’s no way for a provider to verify that an email coming from your domain was actually sent by you. This makes you look suspicious and opens the door for phishers to impersonate your brand, which can destroy your reputation.

Think of it as an official ID for your domain. Setting up email authentication is a foundational step in building trust with ISPs. It tells them you’re a legitimate sender who takes security seriously, making them far more likely to deliver your emails to the inbox.

Ignoring Your Performance Metrics

Your work isn’t done once you hit “send.” Your email performance metrics are a direct reflection of your deliverability health, and ignoring them is a huge mistake. Keep a close eye on your key numbers, including open rates, click-through rates, bounce rates, and unsubscribe rates. These metrics tell a story about how your audience is receiving your content and the quality of your list.

For example, a sudden spike in your bounce rate could indicate a problem with your list quality, while a consistently low open rate might mean you’re landing in the spam folder. Tracking these email marketing KPIs allows you to spot problems early and take action before they cause long-term damage to your sender reputation.

Related Articles

• Newsletter Deliverability | Letterhead
• 9 Newsletter Deliverability Best Practices to Use Now
• The Hidden Fix for Falling Newsletter Engagement: Email Deliverability
• Email Deliverability Best Practices: How to Stay in the Inbox (and Out of Spam)

Frequently Asked Questions

What's the single most important thing I can do for my newsletter's deliverability? While the technical setup is crucial, the most impactful thing you can do is send content that people actually want to read. This starts with building your list organically and using a double opt-in to confirm every new subscriber. An engaged audience that consistently opens and clicks on your emails sends the strongest possible positive signal to inbox providers like Gmail, proving your content is valuable and deserves a spot in the primary inbox.

I think my sender reputation is damaged. How long does it take to fix it? There isn't a magic timeline, as it really depends on how significant the damage is. Rebuilding trust with inbox providers is a gradual process that requires patience and consistency. It could take a few weeks or even a couple of months of positive sending behavior. The best approach is to stop sending to your full list and focus only on your most engaged subscribers for a while. As your metrics improve, you can slowly reintroduce other segments.

Is it really that bad to keep inactive subscribers on my list? I worked hard to get them! I completely understand the hesitation, but yes, it's one of the most common ways publishers hurt their own deliverability. Continuously sending emails to people who never open them tells inbox providers that your content isn't relevant or wanted. This drags down your engagement rates and directly harms your sender reputation, making it more likely that all your emails—even those to your biggest fans—will land in spam. A smaller, active list is always more valuable than a large, dormant one.

My open rates are low. Does that automatically mean I have a deliverability problem? Not necessarily, but it's a definite red flag that warrants a closer look. Low open rates can absolutely be a symptom of a deliverability issue, meaning your emails are landing in the spam or promotions folder. However, they can also be a sign that your subject lines aren't compelling or your content isn't resonating. The best first step is to use an inbox placement test to see where you're landing. This will help you determine if you have a technical problem or a content problem.

I'm not very technical. Is setting up email authentication (SPF, DKIM) something I can do myself? It might sound intimidating, but it's more straightforward than you might think. Most email platforms provide very clear, step-by-step instructions for setting up your authentication records. The process usually just involves copying and pasting a few lines of text into your domain's settings. While it's a critical technical step, it's typically a one-time setup that you can complete in under an hour with a good guide to follow.