When it comes to email marketing campaigns, deliverability is make-or-break.

It doesn’t matter how perfect your email copy is or how targeted your audience—if your message lands in the spam folder, it’s not doing its job.

In a study, the average email deliverability rate in 2024 across the 15 email service providers (ESPs) tested was 83.1%. This means that 16.9% of all emails never reach the intended recipient’s inbox. On average, 10.5% of emails end up in the spam folder, while 6.4% go missing altogether and are considered “undelivered.” In simple terms, this means that nearly 1 in 6 marketing emails never reaches the inbox!

Smartlead – a cold email outreach tool, tackles these issues head-on, helping you overcome deliverability hurdles with a suite of smart features.

It’s designed to ensure your emails make it to the inbox consistently, improving engagement and maximizing your email campaign’s success.

Let’s understand more about email deliverability and its importance for cold email campaigns and how Smartlead is designed to maximize email deliverability for your campaigns.

Why Email Deliverability Is Key for Campaigns

To put it simply, deliverability refers to the number of emails that make it their destination – inbox. It is also known as inbox placement.

However, do note that email deliverability is different from email delivery. Email delivery just refers to the number of emails that are successfully delivered without getting bounced. Deliverability goes a step further by understanding how many are reaching the inbox – thus the name inbox placement. While there is no surefire way to know where your emails are landing in the recipients’ inbox, some email deliverability test (like the one offered by Smartlead – SmartDelivery) helps you understand just that, even before you actually send the campaign (more on this later).

So, deliverability is basically telling you how many emails are reaching the inbox and not the spam folder. Poor deliverability means fewer opens, fewer clicks, and ultimately fewer conversions.

Here’s why deliverability should be a priority:

• Maximized ROI – The more emails that make it to the inbox, the more opportunities you have to convert leads into sales. High deliverability directly influences your revenue potential. 
• Maintained Sender Reputation – Poor deliverability harms your sender reputation, which email service providers (ESPs) rely on to decide whether to flag or filter your emails. 
• Better Engagement – Emails that land in spam never get opened. Consistent inbox placement boosts your chances of getting higher open and click-through rates. 
• Trust and Brand Perception – A poor deliverability track record makes you look untrustworthy. By ensuring your emails reach the inbox, you maintain credibility with both ESPs and your audience.

How Smartlead Improves Email Deliverability

Smartlead helps you overcome deliverability challenges with a powerful set of features designed to boost inbox placement, safeguard your reputation, and optimize campaign results.

Here’s how it works:

1. Unlimited AI-Powered Email Warmups

When you’re just starting with cold email campaigns, you might make the mistake of overlooking the importance of warmups. Warmups are key if you want to improve your domain reputation. It is not just for new domains. You can warm up your domains regularly to maintain a good reputation.

Manual warmups are just not feasible – considering the scale of cold email campaigns.

Rather than doing it manually, which can be tedious and error-prone, Smartlead automates the process with AI that mimics human behavior.

• Scale Your Outreach – You can scale your email outreach without worrying about sender reputation or hitting daily limits. Smartlead’s warmup process grows your account’s reputation over time, allowing you to send more emails confidently. 
• Humanized Sending Patterns – The warm up process isn’t just about volume; Smartlead ensures that emails are sent in humanized, natural patterns to avoid looking like automated spam. 
• Mailbox Diversity – Using over 1.6 million mailboxes from Google, Outlook, and more, Smartlead builds your sending reputation across platforms, improving inbox placement across the board. 
• Spam Rescue – To prevent your mailbox reputation from taking a hit, Smartlead uses a Spam Rescue feature that cloaks warmup emails, making them undetectable by automation filters.

2. SmartDelivery For Email Deliverability Test

SmartDelivery is Smartlead’s cutting-edge solution designed to tackle email deliverability issues. Unlike traditional metrics that often focus on outdated indicators like open rates, SmartDelivery takes a more comprehensive and proactive approach to email deliverability.

So, how does it work?

SmartDelivery allows you to test your emails before sending them to your leads.

It simulates the sending process and analyzes your emails’ performance across various email providers, such as Gmail, Outlook, and Yahoo. This simulation helps you identify potential issues, like being flagged as spam, before they occur. Following is an example of how a SmartDelivery report looks like:

Essentially, SmartDelivery acts as your pre-launch safety net. Whether you’re fine-tuning your subject lines, adjusting your sender reputation, or experimenting with different email accounts, SmartDelivery provides real-time insights into how each tweak impacts deliverability. This means you have a data-driven perspective on your email’s journey, enabling you to make informed adjustments before your campaign goes live.

3. Auto-Rotating Email Accounts

Sending from the same email account repeatedly can lead to email fatigue, affecting both deliverability and engagement.

Smartlead solves this by auto-rotating email accounts, spreading out the workload to keep each account in good standing.

• Effortless Campaign Management – You can connect multiple mailboxes in one step, and Smartlead will automatically rotate accounts with just one click. This reduces the manual effort while maximizing deliverability. 
• Convert More Leads – By rotating accounts, Smartlead ensures that your sender reputation remains high, giving your emails a better chance to reach the inbox and convert leads into customers.

4. High-Delivery IP Rotating Infrastructure

IP addresses play a crucial role in deliverability.

If your emails are coming from a single, overused IP, ESPs might flag them as spam. Smartlead’s IP rotating infrastructure ensures you’re sending from a fresh, healthy pool of IPs to keep your deliverability rates up.

• Unique IP Allocation – Each campaign is allocated its own exclusive IP address, which helps avoid deliverability issues caused by overuse or sharing. 
• Dynamic IP Allocation – Smartlead automatically switches between pre-warmed and fresh IPs, maintaining a balance that maximizes deliverability. 
• Deliverability-Tested IPs – Only IPs that have passed deliverability tests are used, ensuring you’re working with the best possible infrastructure for sending.

5. ESP Matching to Bypass Email Filters

Different ESPs like Gmail and Outlook have unique spam filters.

Matching your sending server with your recipient’s ESP is critical to improving deliverability.

Smartlead’s ESP matching feature handles this automatically, boosting your chances of hitting the inbox.

• Automated ESP Matching – Smartlead’s dynamic ESP matching algorithm pairs your sending domain with the best ESP for your recipient, helping you avoid filters and improve inbox placement.

6. Auto-Adjusting Warm up Reply Rates

Reply rates are a key signal to ESPs that your emails are engaging.

Low reply rates can negatively impact your sender reputation, while consistent replies can boost your standing. Smartlead’s auto-adjusting feature tracks campaign performance and adapts reply patterns on the fly.

• Real-Time Pattern Adjustments – Smartlead’s AI analyzes reply rates in real time, automatically adjusting sending behavior to emulate healthy, natural interactions. 
• Offset Low Reply Rates – When reply rates drop, Smartlead responds by increasing warmup reply rates, balancing your account’s reputation and maintaining strong deliverability.

7. Send Emails That Don’t Look Like Cold Emails

Cold emails are notoriously harder to deliver, often flagged as spam or ignored. Smartlead’s delivery-optimization feature makes your cold emails look like natural conversations, boosting reply rates and improving inbox placement.

• Boost Reply Rates by 18-22% – Smartlead makes it easy to send plain-text emails that fit naturally into your lead’s inbox. This format bypasses many filters while improving reply rates. 
• Maintain Formatting – You don’t have to sacrifice email formatting to improve deliverability. Smartlead ensures your emails maintain their design integrity while increasing their chances of being opened and replied to.

8. Spintax: Personalize at Scale

Personalization is crucial to getting engagement, but manually tailoring every email is unrealistic at scale. 

Spintax allows you to personalize your emails dynamically, creating unique variations without the extra workload.

• Create Dynamic Content – With spintax, you can insert placeholders for different variations of names, company info, and more, so every email feels tailored, even when you’re sending to hundreds or thousands of leads. 
• Avoid Spam Traps – Spintax helps avoid repetitive, robotic-sounding messages, reducing the likelihood that your emails will trigger spam filters. 
• Effortless Personalization – You don’t need to manually craft each email. spintax generates variations on the fly, ensuring every message feels human and increases the chance of engagement.

Tips To Improve Email Deliverability

Improving email deliverability is all about ensuring that your emails end up in the inbox rather than the spam folder. It’s not just about hitting the send button; it’s about sending emails in a way that maximizes your chances of being seen and read. 

Here are several actionable tips to help you achieve better inbox placement:

Authenticate Your Emails

Authentication is a key step in making sure your emails are recognized as legitimate. Ensure your emails are authenticated with protocols such as SPF, DKIM, and DMARC.

• SPF (Sender Policy Framework): This protocol helps verify that the sending server is authorized to send emails on behalf of your domain. 
• DKIM (DomainKeys Identified Mail): DKIM adds a digital signature to your emails, ensuring they haven’t been altered in transit. 
• DMARC (Domain-based Message Authentication, Reporting & Conformance): DMARC ties it all together, instructing receiving servers on how to handle messages that fail SPF or DKIM checks.

Together, these protocols act as a passport for your emails, ensuring they pass through security checks and land where they’re supposed to.

Use Clean Email Lists

Your email list is the backbone of your campaign. Sending to outdated or unverified email addresses can result in hard bounces, which negatively impact your sender reputation. Regular maintenance is key.

• Regularly Clean Your Lists: Take the time to remove inactive or invalid contacts. This not only improves deliverability but also increases engagement rates. 
• Use Verification Tools: Employ email verification tools to ensure the addresses on your list are valid and reachable. This proactive approach keeps your list fresh and reduces the risk of bounces.

Personalize Your Emails

Personalization goes beyond just inserting the recipient’s name. Using generic templates repeatedly can trigger spam filters, so it’s essential to craft emails that feel authentic.

• Dynamic Content: Tools like Spintax allow you to create variations in your emails, which makes each message feel unique to the recipient. This enhances the reader’s experience and reduces the likelihood of being flagged. 
• Tailored Messaging: Consider the interests and needs of your recipients. A message that resonates personally is more likely to be opened and engaged with.

Monitor Your Sending Frequency

Your sending frequency can significantly impact your deliverability. If you send too many emails too quickly, it may overwhelm recipients and raise red flags with ESPs.

• Gradual Scaling: Increase your sending volume slowly over time, especially when launching new campaigns. This helps you avoid being perceived as spammy. 
• Space Out Your Emails: Maintain a consistent sending schedule. Spacing out your emails allows recipients to engage with them rather than feeling bombarded.

Test Your Emails

Before hitting send on a large campaign, it’s vital to run deliverability tests. This step gives you insights into how your emails might perform across different ESPs.

• Use Testing Tools: Tools like SmartDelivery (available on Smartlead) can show you how your emails will be treated by various ESPs. You’ll get a clearer picture of potential issues before going live. 
• Adjust Based on Feedback: Use the insights from these tests to tweak your subject lines, content, or sending patterns. This preemptive approach can save you from deliverability headaches down the line.

Following these simple strategies can significantly increase your chances of landing in the inbox, keeping your email campaigns effective and impactful.

Published by: Josh Tatunay