The Ultimate Guide To Email Deliverability In 2026

What Is Email Deliverability?

Email deliverability refers to the ability of your emails to successfully reach your recipients’ inboxes, not just be accepted by their mail server. This is a crucial distinction from your email delivery rate, which only tracks whether the email bounced or not.

💡 Deliverability depends on several factors, including authentication (SPF, DKIM, DMARC), sender reputation, list hygiene, content quality, and recipient engagement.

A high delivery rate doesn’t guarantee inbox placement; only good deliverability practices do.

In short, deliverability is about ensuring your email lands where it matters most: the inbox.

Why does email deliverability matter?

Landing in the inbox is just the first step, but if you don’t get that right, nothing else you do with the message matters.

📌 Impact on Engagement and Campaign Results

Without strong deliverability, engagement plummets. For instance:

• Data from GlockApps shows the average inbox deliverability rate for senders (who send between 200,000 and 1,000k emails per month) improved from 49.77% in Q1 2024 to 60.96% in Q1 2025.
• Another study found the average email deliverability rate across 16 email service providers (ESPs) in 2024 was 83.1%. That means roughly 16.9% of marketing emails never reached the inbox.
• According to a survey, 93% of people check their email daily, while 42% say they check 3 to 5 times a day.

What these numbers show: if your deliverability is poor, then a significant portion of your audience will never see your message and consequently will never act on it (open, click, convert).

📌 How Deliverability Affects Engagement Metrics

Let’s walk through a simplified scenario. Suppose you send 100,000 emails. If your deliverability is 90% (i.e., 90,000 reach the inbox) vs. 70% (i.e., only 70,000), you’re already missing 20,000 opportunities.

If your open rate among delivered emails is 20%, in the first case, you get 18,000 opens; in the second case, only 14,000. That’s a drop of ~22%.

Simply put, deliverability multiplies the impact of every other metric, from how many people get your email to how many open, click, and buy. If fewer messages reach the inbox, every result that follows automatically drops, too.

📌 Reputation, Trust, and Future Sends

Beyond immediate engagement, deliverability affects your long-term sender reputation.

A strong reputation means fewer bounces, spam reports, and blocks, which, in turn, helps with future sends. A weak reputation can lead to your messages being throttled, filtered, or blocked outright.

📌 ROI and Business Impact

Email remains one of the highest-performing marketing channels. For example, some reports quote an ROI to be between $36 and $40 for every $1 spent. But all that ROI depends on the message arriving and being engaged with.

With average deliverability rates hanging around 83.1% (or lower in some segments) in 2024, marketers are losing a substantial portion of their potential reach.

In short, deliverability determines if all the work you put into your emails, from setup to design to content, actually reaches people and drives results.

How Is Email Deliverability Measured?

Mail deliverability is measured using a metric called the Inbox Placement Rate (IPR). The IPR is the percentage of messages that have been successfully delivered to the recipients' inboxes, as opposed to being marked as spam or bouncing back. To calculate it, you simply divide the number of messages delivered to the inbox by the number of messages sent, and then multiply the result by 100.

For example, if you send 1000 messages and 900 of them reach the recipients' inboxes, your IPR would be 90%.

When asked, "What is a good email deliverability rate?" most experts recommend aiming for a deliverability rate of 95% as the best email deliverability rate you should realistically strive to achieve.

That said, every single IPR percentage point counts because it can have a significant impact on your bottom line. Imagine a business that sends 10,000 messages per month, with a current Inbox Placement Rate (IPR) of 80%. We’ll assume a conversion rate of 2% and that each conversion generates $50 in revenue. By boosting the IPR from 80% to 85%, the business can earn an additional $6,000 annually.

How to Test & Monitor Email Deliverability

Regular email deliverability testing and monitoring should be part of your email deliverability checklist to help catch issues early, protect your reputation, and optimize for better performance.

1. Seed Testing & Inbox Placement Audits

Seed testing involves sending your email to a controlled list of test inboxes across major providers, such as Gmail, Outlook, Yahoo, and Apple Mail, to see exactly where it lands (Primary, Promotions, or Spam).

2. Authentication & Technical Diagnostics

Authentication failures are one of the most common reasons for poor deliverability.

• Check SPF, DKIM, and DMARC alignment regularly using tools like MXToolbox or Google Postmaster Tools.
• If you use multiple sending domains or subdomains, ensure each one is fully authenticated.
• Consider adding BIMI (Brand Indicators for Message Identification) to boost trust and brand recall.

3. Track Key Deliverability Metrics

Keep an eye on the numbers that show how healthy your email program is. Track these regularly:

• Inbox placement rate. The percentage of emails that actually land in inboxes (not spam). Aim for 90% to 95% or higher.
• Bounce rate. How many emails fail to reach any inbox at all. Try to keep this under 1.0% by cleaning your list often.
• Spam complaint rate. How many people mark your email as spam. Anything above 0.01% is a red flag for mailbox providers.
• Engagement signals. Opens, clicks, replies, or even how long people spend reading your emails. These all tell inbox providers that your messages are worth keeping.
• Authentication pass rate. Make sure your technical settings (SPF, DKIM, and DMARC) pass 100% of the time so your emails look trustworthy.

4. Reputation & Blocklist Monitoring

Think of your sender reputation like an indicator for your emails: it tells mailbox providers whether they can trust you. Even one small blocklist entry can seriously hurt your chances of landing in the inbox.

• Use reputation and blocklist monitoring tools, such as Talos, Spamhaus, or Google Postmaster Tools, to check your sender status regularly.
• If you notice a sudden rise in bounces or spam complaints, act fast. Don’t wait for it to fix itself.
• To rebuild trust, send smaller batches of emails to your most engaged subscribers first, then slowly scale up again.

5. Deliverability Trend Analysis

Don’t just look at one campaign’s results. The real insights come from watching patterns over time.

• Compare performance by campaign, list segment, sending domain, or IP address.
• Spot which types of emails get the best engagement and which ones might be dragging your sender reputation down.
• Use these trends to guide future campaigns and decide when it’s time to clean your list or adjust your content.

How to Achieve a High Email Deliverability Rate?

Achieving a high mail deliverability rate is not a one-time task, but rather a continuous process that requires a multi-pronged approach. In this section of our mail deliverability guide, we'll explore the key strategies and best practices that can help you improve mail deliverability so that your messages land in your recipients' inboxes.

Factors affecting email deliverability

Before you fix issues, you need to understand what drives inbox placement. Email deliverability is influenced by a mix of technical setup, sender reputation, and recipient behavior.

📌 Additional key factors to monitor:

• List quality: Poor hygiene leads to high bounce and complaint rates.
• Send consistency: Spikes in volume can trigger spam filters.
• Content signals: Overly promotional or spammy wording can flag filters.
• User engagement: High engagement = better placement. Low engagement = higher spam risk or increased filtering.
• Regulatory compliance: Non-compliance (e.g., missing unsubscribe links) can get you flagged fast.

According to Salesforce, analyzing key deliverability KPIs is critical for sustained email delivery success. A blog post from Amazon Web Services emphasizes that tracking metrics is a core best practice for list management and sender reputation.

Some of the tools you could use to build your dashboard include Excel or Google Sheets, Power BI, or Amazon Simple Email Service (SES).

With a dashboard, you can easily evaluate which campaigns, lists, or behaviors have the strongest (or weakest) impact on inbox placement. Lastly, a dashboard can help you move from reactive (“Why did this campaign fail?”) to proactive (“Our drop in inbox placement started two weeks ago; let’s act now”).

How to improve email deliverability

The good news? Even if your deliverability isn’t perfect, you can turn it around by following email deliverability tips. Improvement entails layering multiple best practices to build trust with ISPs.

✅ Core checklist for improving email deliverability:

• Authenticate your sending domain (SPF, DKIM, DMARC, BIMI, where possible).
• Keep your list clean with regular verification and pruning.
• Provide a visible, easy unsubscribe option to reduce spam complaints.
• Send relevant, personalized content to drive engagement signals.
• Warm up new IPs and domains gradually to build reputation.
• Segment audiences to increase engagement rates. Per Omnisend, email segmentation can help drive conversion rates by 27.6%. Moreover, segmented campaigns have a 23% higher average open rate compared to non-personalized emails.
• Maintain consistent sending patterns rather than erratic volume spikes.
• Regularly monitor performance and make data-driven adjustments.

📌 Engagement-boosting tactics:

• Personalize subject lines and copy to match user intent.
• Test send times and frequencies. Remember, sometimes less is more.
• Use double opt-in to ensure you’re emailing people who actually want to receive your messages.
• Run re-engagement campaigns for inactive subscribers, or remove them if they stay silent.

Let’s discuss some of the approaches to improve email marketing deliverability in more detail:

📌 Maintain a good sender reputation

Your sender reputation is like your credit score in the email world. It's a measure of the trustworthiness of your emails in the eyes of Internet Service Providers (ISPs).

Whenever you send an email, the message is forwarded by multiple ISPs before it reaches the recipient's inbox. These ISPs check where the message comes from and whether the IP address has a good reputation. If the IP address doesn't have a good reputation, the ISPs may decide to block the email, which will negatively impact your email deliverability rate.

ISPs use several factors to determine email deliverability and sender reputation, including:

• The number of messages sent from the IP address
• The number of spam complaints from recipients
• The number of messages that bounce back
• The number of messages that are opened and clicked by recipients
• The presence of the IP address on blacklists

To protect your sender reputation, you should never send messages from a shared IP address because your internet neighbors may engage in activities that could harm your reputation. Instead, it's recommended to use a dedicated IP address, which is reserved solely for your use.

Alternatively, you can use reliable email marketing platform like Mailchimp, Brevo, or Constant Contact. All of these platforms have spent a ton of money to build a strong reputation with ISPs, which means that your messages are more likely to land in the inbox when they originate from their servers. As a nice bonus, email marketing platforms often include various email deliverability tools to help their users monitor and improve this important metric.

📌 Configure email authentication standards

Email authentication standards are used to add legitimacy to your emails, making it easier for ISPs to trust your messages and deliver them directly to your recipients' inboxes. These standards are like ID cards for your messages because they verify the identity of the sender so that the recipient can be confident that the email is legitimate and not a phishing or spam attempt.

The technical foundation of email authentication consists of three main protocols:

• SPF (Sender Policy Framework): Allows you to specify which mail servers are permitted to send email on behalf of your domain.
• DKIM (DomainKeys Identified Mail): Adds a digital signature to the headers of your messages. This signature is linked to your domain name to provide a way to verify that the message was not altered after it was sent.
• DMARC (Domain-based Message Authentication, Reporting, and Conformance): Provides additional instructions to ISPs on how to handle emails that don't authenticate and also includes reporting capabilities.

The implementation of these standards is a cornerstone of mail deliverability best practices because their absence can lead to a significant decrease in the number of emails that reach the intended recipients' inboxes. In other words, without email authentication standards, your emails are more likely to end up in the spam folder or be blocked altogether.

📌 Keep your email list healthy

Even if your messages are originating from a reputable IP address and are authenticated properly, there's still a lot that you can do to boost your email deliverability. The key is to shift your attention to your list of intended recipients.

Here are some techniques and strategies for list hygiene and management that can help you improve mail deliverability:

1. Get rid of inactive or invalid email addresses

It's important to regularly remove inactive or invalid email addresses from your list. Inactive subscribers are those who haven't engaged with your emails for a certain period of time, while invalid addresses are those that have been entered incorrectly, have become obsolete, or no longer exist.

Keeping these addresses on your list can lead to high bounce rates and low engagement, which negatively impact your mail deliverability and sender reputation.

The good news is that there are many email deliverability test tools, including VerifiedEmail, that can help you prune your list in no time.

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2. Avoid spam traps

Spam traps are email addresses that are set up by ISPs or anti-spam organizations to catch spammers. If you send a message to a spam trap, it can harm your sender reputation and result in a lower IPR. To avoid spam traps, you should regularly test email deliverability and remove all contacts that are flagged accordingly or haven't engaged with you in a long time.

It's also important to use a double opt-in process for new subscribers so that only legitimate addresses are added to your list. This means that after someone signs up for your email list, they receive a confirmation message that they must click on to complete the subscription process.

3. Don't engage in shady practices

While it may be tempting to take shortcuts to boost your email marketing, engaging in shady practices can have serious consequences for your mail deliverability.

For example, you should never purchase an email list to reach more potential customers. Not only is this practice illegal in many countries, but such lists almost always contain many outdated or inaccurately collected addresses, including spam traps.

You also shouldn't write misleading subject lines to boost your open rates. When the subject line doesn't reflect the content of the message, the recipient is more likely to flag the message as spam, and that's the last thing you want to happen.

Email Deliverability Tools

Deliverability tools are also for prevention, optimization, and scaling.

1. Inbox Placement & Pre-Send Testing Tools

Some services let you simulate how different mailbox providers treat your emails. You can see placement by segment, preview layouts, and fix issues before sending.

2. Reputation and Blocklist Monitoring Tools

A strong sender reputation takes time to build and seconds to lose. Most tools, like Google Postmaster Tools, provide alerts and dashboards to help you stay ahead of issues. Monitor metrics like spam rates, IP reputation, and delivery errors.

3. Email Verification & Hygiene Platforms

Clean lists keep your email deliverability guide strategy solid. Tools that identify invalid or risky addresses prevent spikes in bounce rates and help maintain trust with ISPs.

4. Engagement Analytics And Reporting

Beyond open rates, modern analytics tools measure replies, forwards, scroll depth, and device engagement. These deeper insights tell ISPs your content is valuable, boosting placement over time.

Key Deliverability Factors to Watch in 2026

For 2026, several emerging factors will influence email deliverability more than ever, including:

1. Reinforced Authentication & Brand Verification

Standards like DMARC alignment and BIMI are gaining importance. According to Attentive, one of the most significant deliverability trends includes BIMI and stronger authentication frameworks.

For 2026, expect mailbox providers to enforce stricter alignment, meaning senders without fully aligned SPF/DKIM/DMARC/BIMI sets may face higher filtering or blocking.

2. AI-driven Filtering & Engagement Scoring

With the explosion of spam and bulk sending, email providers are deploying advanced machine learning systems to gauge not just whether a message is spam, but whether it engages recipients. MarTech reported that by 2026, around 70% of marketers expect AI to handle up to half of their email marketing tasks.

Based on insights from Mailpool, this means that even if your technical setup is sound, if recipient engagement is low (opens, replies, clicks, forwards), that may affect your placement. The focus will shift more toward “did the recipient meaningfully interact with the message?” rather than just “did it get delivered?”

For 2026, marketers must craft content and send strategies that drive real engagement, not just clicks. Think: replies, forwards, and meaningful actions that prove legitimacy.

3. Hyper-Segmentation, Personalization & Journey-Based Sends

Campaign Refinery reported that email marketers who use segmentation can earn up to three times more revenue than those who send the same message to everyone.

In 2026, ISPs are likely to reward senders whose emails are highly relevant to the individual subscriber. A one-size-fits-all campaign may not only underperform but also risk placement in the Promotions tab or spam folder.

Senders will need to map full subscriber journeys, dynamically segment by behavior, and send content that truly reflects where each recipient is.

4. Privacy, Consent & Regulatory Pressure

With global regulations tightening, consumer trust is now more critical. Attentive’s trend analysis points out the increased emphasis on list hygiene and cold sender penalties.

ISPs increasingly view cold or purchased lists, or unsubscribed subscribers, as a signal of low-quality sending. In 2026, you’ll need to follow standards to create better user experiences. For example, you can create transparent opt-in flows and regularly check spam compliance rates.

Non-compliance or poor consent practices can incur legal risk and impact your sender reputation and deliverability.

5. Mobile & Device Behavior Influence

Email consumption continues to lean toward mobile. Per OptinMonster, 50% of users delete emails if they’re not mobile-optimized.

In 2026, mail providers will likely monitor how mobile recipients interact (scroll depth, taps, conversions). Poor mobile UX may hurt engagement signals and affect deliverability.

Ensuring mobile-first design, fast loading, and clear calls to action will be key for opens and conversions, as well as deliverability itself.

6. Real-Time Feedback Loops & Interactive Engagement

Feedback loops (reports from mailbox providers about spam complaints, engagement thresholds) are becoming more prevalent. As more inbox service providers open real-time or near-real-time loops, senders who only look at aggregated data will be at a disadvantage.

For 2026, integrating real-time feedback, anomaly detection (e.g., sudden drop in opens), and adjusting strategy mid-campaign are likely to become standard.

Additionally, interactive email elements (AMP for Email, embedded surveys) may increase engagement, thereby improving deliverability indirectly.

7. Domain & IP Ecosystem Complexity

As more senders use multiple domains, sub-domains, and IP rotations, ESPs will place more emphasis on domain and sender reputation, according to Kulea.

Per Suped co-founder and CTO Matthew Whittaker, if you’re sending from new domains or using many sub-domains in 2026, you’ll need to warm them up with smaller, high-engagement sends. Monitoring their reputation distinctly from legacy domains also helps.

Failure to do so may lead to a “new domain penalty,” where emails are filtered or blocked until trust is established.

8. Market Growth & Tool Innovation

The market for email deliverability tools is projected to grow from USD 1.24 billion in 2024 to USD 1.35 billion in 2025.

For the next year, we may see new tool categories designed to supercharge email deliverability features. Based on analysis from Mailgun, it’s likely that we’ll also be seeing user-first email with more focus on three key aspects: authentication, compliance, and accessibility.

Conclusion

Email deliverability can make or break your marketing campaign, so learning what it is and how to improve it is essential for any marketer or business owner. And with tools like VerifiedEmail, you can easily test and monitor your mail deliverability to ensure that your messages are reaching your intended recipients.

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