Email deliverability [2025 Guide to ensure inbox success]

Email marketing offers one of the highest returns on investment, with $42 for every $1 spent.

But if your emails don't reach the inbox, that potential is wasted.

Here are some fascinating email deliverability statistics that provide valuable insights:

• Global email deliverability for marketing emails averages between 83% and 85% in 2025.
• Top-performing ESPs have seen inbox rates drop by 27.75% and 9.99% respectively, from 2024.
• Bounce rates in industries like eCommerce are as low as 0.57%, showing strong list hygiene practices.
• 64.6% of businesses report that email deliverability issues negatively impact revenue and customer retention.

These studies highlight the increasing challenges email marketers face in ensuring their emails land in the inbox. With more stringent filters, declining inbox rates, and a significant impact on revenue, it's more important than ever to focus on optimizing email deliverability.

This guide provides actionable insights on how to improve your email deliverability, avoid common pitfalls, and ensure your emails consistently reach the right audience.

What is email deliverability?

Email deliverability refers to the ability of your emails to reach the recipient's inbox rather than being filtered into spam or junk folders.

Unlike the delivery rate, which only tracks whether the server accepted your email, deliverability focuses on whether your emails end up in a place where they can be read and acted upon.

Key metrics that affect email deliverability include email delivery rate, open rate, and engagement.

Identifying and resolving email deliverability issues early can help ensure your emails make it to the inbox, leading to better engagement and ultimately stronger business results.

Why is high email deliverability important?

In email marketing or cold emailing, deliverability is a key factor in ensuring your messages are seen.

Better deliverability leads to improved engagement and stronger campaign performance. Poor deliverability means your emails may end up in spam, resulting in missed opportunities for interaction and conversions.

For a higher cold email deliverability, it's essential to use best practices like warming up your email domain and personalizing outreach to ensure high deliverability rates.

The more engaged your audience, the higher your conversions. In a crowded inbox, it's critical that your emails stand out and aren't buried by spam filters.

Mailbox providers like Gmail and Yahoo play a crucial role in determining whether your emails land in the inbox or are filtered as spam.

Five core factors affect email deliverability

Understanding these five key factors can help you boost inbox placement, increase engagement, and improve your campaign's success:

1. Sender reputation

Your sender reputation is one of the biggest factors in determining whether your emails land in the inbox or get flagged as spam.

• IP reputation: This is shaped by how consistent your sending patterns are. If you frequently send large volumes of emails with high complaint rates or trigger spam traps, your IP can get blocked.
• Domain reputation: This comes down to your domain's history. A clean domain with minimal complaints and strong engagement helps improve your deliverability over time.

2. Authentication protocols

Being recognized as a legitimate sender by email providers is essential for high deliverability.

Email authentication protocols like SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting & Conformance) play a crucial role in ensuring your emails are legitimate and not flagged as spam or phishing attempts.

These protocols help ISPs (Internet Service Providers) verify that the sender is who they claim to be and that the email hasn't been tampered with.

3. List quality & hygiene

Maintaining a clean and engaged email list is essential for better deliverability. A poorly maintained list, with invalid or inactive email addresses, can lead to high bounce rates and spam complaints.

• Use double opt-in methods to ensure recipients genuinely want your emails.
• Regularly clean your list by removing bounced addresses and disengaged recipients to improve engagement rates.

4. Content & technical setup

The content of your emails plays a major role in determining whether spam filters will flag your emails.

• Subject lines: Avoid spammy words like "free," "limited time," or "urgent" that could trigger spam filters.
• HTML-to-text ratio: Ensure a balanced email that doesn't have too many images or a heavy HTML design, which can make emails look like spam.

5. Sending infrastructure & schedule

How you manage your email sending infrastructure is crucial.

• Warm-up new IPs: If you're sending emails from a new IP or domain, gradually increase your sending volume. Sudden spikes in volume can make you appear suspicious to email providers.
• Dedicated IP address: For high-volume senders, using a dedicated IP ensures your reputation is kept separate from others who may have poor practices.
• Optimal send times: Analyzing past engagement data and choosing the right time to send your emails can increase open rates and improve deliverability.

To improve email deliverability, focus on optimizing your sender reputation, using proper authentication protocols, and maintaining a clean email list.

Now that you understand the key factors influencing email deliverability, let's move to the email deliverability best practices 2025 in detail.

How to improve your email deliverability?

Implementing email deliverability best practices, such as proper authentication and maintaining list hygiene, can help ensure your emails consistently land in the inbox.

These strategies outline how to fix email deliverability and ensure your emails reach the inbox.

1. Build and maintain a strong sender reputation

Your sender reputation is the foundation of email deliverability.

If your reputation is strong, email providers will trust your emails and deliver them to the inbox. If it's weak, your emails could end up in the spam folder.

• Gradually increase email volume: If you're using a new IP or domain, start with smaller email batches and increase volume gradually. This helps build trust with email providers.
• Use a dedicated IP: For high-volume senders, using a dedicated IP ensures your reputation is kept separate from others who may have poor practices.
• Focus on active recipients: Regularly clean your list by removing inactive subscribers and concentrate on users who engage with your emails. This will help maintain a higher engagement rate and improve deliverability.

2. Implement authentication and security protocols

Authentication ensures that your emails are legitimate and not impersonated by spammers or phishing attempts. Without proper authentication, your emails are more likely to be flagged or rejected.

• Set up SPF, DKIM, and DMARC: Ensure these authentication protocols are set up correctly to prove your emails are coming from a trusted source.
• Monitor your DMARC reports: Regularly check your DMARC reports to ensure that your emails are passing authentication and that there are no issues with your setup.

3. Maintain list hygiene and engagement

A clean, engaged email list is key to high deliverability and lower bounce rates.

• Use double opt-in: Implement a double opt-in process to ensure only subscribers who genuinely want to receive your emails are added to your list.
• Clean your list regularly: Remove hard bounces, users who haven't engaged for a long time, and those who've unsubscribed or marked your emails as spam. Keeping your list clean will reduce bounce rates and complaints.
• Segment your list: Divide your list into segments based on engagement levels, demographics, or behavior. Targeting the right recipients ensures higher open rates and better engagement.

4. Optimize your email content

The email message itself plays a critical role in deliverability and engagement.

Spam filters and recipients' behavior can both be influenced by how your email is crafted.

• Avoid spam-triggering words: Words like "free," "urgent," or "limited time" can cause your email to be flagged. Stick to clear, straightforward subject lines and avoid over-hyped language.
• Maintain a healthy HTML-to-text ratio: Too many images or a heavy HTML design can flag your email as spam. A good balance of text and HTML ensures better deliverability.
• Personalize content: Tailoring your emails based on the recipient's interests or behavior increases the relevance of your message and improves engagement rates. For example, addressing recipients by name or recommending products based on their past purchases makes the email feel more personal and less likely to be ignored.

Understanding spam filter behavior is key to avoiding filters that could send your emails to the spam folder.

Spam filters evaluate factors such as subject lines, content structure, and the presence of spammy words or phrases. By optimizing your email content, you can bypass these filters.

5. Monitor your email infrastructure

How you manage your email sending infrastructure and technical setup plays a significant role in your deliverability.

• Warm-up new IPs: When sending from a new IP or domain, gradually increase the volume of emails to avoid triggering spam filters.
• Monitor blocklists: Regularly check if your domain or IP has been added to any blocklists. If it has, take immediate steps to resolve the issue.
• Send time optimization: Analyze past engagement data to determine the optimal times for sending emails to maximize open rates and engagement.

Insightful: Best time to send cold emails (Boost your open rates in 2025)

6. Handle complaints and feedback promptly

Taking care of feedback and complaints quickly is essential for protecting your sender reputation and keeping your emails out of spam folders.

• Register for feedback loops (FBL): Sign up with major email providers (like Gmail, Yahoo, or Microsoft) to receive direct notifications when recipients mark your emails as spam. This allows you to quickly remove those subscribers and reduce the risk of further complaints.
• Act quickly on complaints: If someone reports your email as spam, act promptly by removing them from your list and adjusting your email practices if needed. Being responsive to complaints is crucial for maintaining a positive sender reputation.

How to monitor your email deliverability?

The average email delivery rate typically ranges from 80% to 95%, which reflects the percentage of emails that successfully reach recipients' inboxes.

Monitoring deliverability metrics is essential for tracking the effectiveness of your email campaigns and ensuring they reach the inbox.

Here are the key deliverability metrics you should monitor regularly:

• Inbox placement rate: This is the percentage of emails that land in the recipient's primary inbox. A low inbox placement rate means your emails may be filtered into spam or promotions folders. Aim for a rate above 95% for optimal deliverability.
• Spam complaint rate: This tracks how often recipients mark your emails as spam. A high spam complaint rate can hurt your sender reputation and lower deliverability. Keep it below 0.1% to ensure healthy inbox placement.
• Bounce rate: Bounce rate measures how many of your emails couldn't be delivered due to invalid or unreachable email addresses. A high bounce rate suggests list quality issues that need to be addressed. Keep your bounce rate under 2% for optimal results.
• Sender score & reputation: Your sender score reflects the health of your IP/domain. A higher score indicates that your emails are more likely to be trusted by email providers. Regularly check and monitor your sender score to avoid delivery issues.
• DMARC aggregate reports: DMARC reports help you monitor the alignment of your email authentication protocols (SPF, DKIM). These reports provide valuable insights into any authentication failures, allowing you to address issues and ensure your emails pass authentication checks.

Regularly monitor these metrics to identify trends and potential issues.

For example, if your inbox placement rate drops, investigate whether your content or list hygiene might be to blame.

Use these insights to make data-driven decisions. If your bounce rate is high, it may be time to clean up your list. If spam complaints are rising, it could indicate a need to adjust your email content or targeting strategies.

How do you measure email deliverability?

To ensure your emails reach your recipients' inboxes and not get filtered into spam or junk folders, regularly checking your email deliverability is crucial.

Here's how you can do it effectively:

• Run inbox placement tests: Tools like Litmus or GlockApps simulate how different inbox providers treat your emails and show if they're landing in the inbox or being filtered into spam or promotions.
• Monitor sender reputation: Use Sender Score or other reputation tracking tools to monitor how your email IP and domain are performing. A positive sender reputation is key to avoiding deliverability issues.
• Verify authentication protocols: Check if your emails pass SPF, DKIM, and DMARC authentication using tools like MXToolbox. This helps ensure that your emails are verified and trusted by ISPs.

By performing these checks, you can proactively address deliverability issues and improve your email marketing efforts.

Also read: AI in email marketing [Smarter campaigns that convert fast]

Best email deliverability tools for optimizing deliverability

To maximize deliverability, it's important to use tools that help with email deliverability monitoring, track your reputation, test inbox placement, and maintain a clean list.

Here are some key email deliverability solutions:

Email Service Providers (ESPs)

Choosing the right email service provider (ESP) is critical for ensuring high deliverability.

Email deliverability tools like Mailgun and SendGrid offer advanced features to monitor and improve your inbox placement, ensuring higher engagement with your audience.

These email deliverability software help ensure your emails are sent from trusted servers and deliver them to the inbox rather than spam folders.

Reputation monitoring tools

A strong sender reputation is essential for maintaining high deliverability.

Tools like Return Path, 250ok, and Talos Intelligence help monitor the health of your IP/domain and track your sender reputation.

These tools allow you to proactively identify and resolve issues that could negatively impact your deliverability.

Inbox placement testing tools

Before sending out large campaigns, it's important to test how spam filters will treat your emails.

Running an email deliverability test with tools like Litmus or GlockApps ensures that your emails pass through spam filters and land in the inbox.

These tools provide valuable feedback so you can optimize your emails for better performance.

List validation services

Maintaining a clean email list is crucial for high deliverability.

Services like ZeroBounce and NeverBounce validate email addresses to ensure that your list is free of invalid or non-engaging contacts. This improves list quality, reduces bounce rates, and boosts deliverability.

Must check: 25 Best AI marketing tools (by category) to use in 2025

Email deliverability checklist to save

Consistent monitoring and optimization are key to maintaining high email deliverability and engagement over time.

• Verify SPF, DKIM, and DMARC quarterly: Ensure that your authentication protocols (SPF, DKIM, and DMARC) are up-to-date. This helps prevent spoofing and builds trust with email providers, ensuring your emails are seen as legitimate.
• Perform list hygiene weekly: Regularly clean your email list by removing hard bounces, complaints, and inactive users. Keeping your list fresh ensures higher engagement and fewer deliverability issues.
• Monitor reputation dashboards daily: Track your IP/domain reputation daily to address any issues quickly. Keeping an eye on your reputation helps prevent your emails from being flagged as spam, ensuring better inbox placement.
• Run inbox placement tests before major campaigns: Before launching major email campaigns, test your emails with tools like Litmus to see how they perform across different inboxes. This helps you identify and fix any potential deliverability issues before they impact your results.
• Document changes and outcomes: Keep a record of all optimizations and the results they yield. Tracking changes will help you continuously refine your email strategies for even better performance over time.

Conclusion

Email deliverability is a key factor in ensuring your marketing efforts reach the right audience.

By maintaining a strong sender reputation, optimizing your email content, and regularly monitoring key metrics, you can significantly improve your inbox placement and engagement rates. 

Leveraging the right tools and continuously refining your strategies will help you stay ahead of deliverability challenges.

With Salesmate, you can automate your email campaigns, track deliverability metrics in real-time, and seamlessly manage your email lists.