Email Deliverability: Overview, Key Factors & Best Practices

Email Deliverability: What Is It, Key Factors & Best Practices

Email Deliverability: What Is It, Key Factors & Best Practices - Blog Article

What is Email Deliverability?

Email deliverability refers to the ability of an email to successfully reach the intended recipient’s inbox.

Think of it like mailing a letter and making sure it lands right in the recipient’s hands, not lost or thrown away. It’s an important measure for anyone sending out emails, as it affects whether your message is seen or goes unnoticed.

Deliverability works by navigating through various email service provider (ESP) filters and policies. When you send an email, ESPs evaluate it based on factors like sender reputation, content, and recipient engagement. If the email meets their criteria, it lands in the inbox; otherwise, it might end up in the spam folder or be blocked entirely.

Email Delivery vs. Deliverability: What’s The Difference?

Email delivery and deliverability might sound similar, but they focus on different parts of the email sending process. Here’s how they differ:

  • Email delivery is about whether your email can enter the recipient’s email system at all. It’s the first step—like checking if your letter can be dropped into the mailbox. If an email address is wrong or the recipient’s inbox is full, your email won’t be delivered.
  • Email deliverability, on the other hand, goes one step further. It’s about where your email ends up once it’s inside the system. Even if your email is delivered, it’s not helpful if it lands in the spam folder. Deliverability is about getting your email into the main inbox, where it’s more likely to be seen and read.

For example, if you send an email and it doesn’t bounce back, that means it’s been delivered. But, if the recipient never responds, it might be because the email didn’t make it to their main inbox—that’s a deliverability issue.

Email Deliverability Funnel

Why Email Deliverability Matters?


A 1% increase in email deliverability could mean thousands of dollars in revenue.

Email deliverability is crucial because it directly impacts whether your message is seen or ignored. When more of your emails land in the main inbox, more people see your message, which can lead to more sales, more engagement, and stronger customer relationships.

For instance, if you’re running an online store and you send out a coupon code to your customers, email deliverability issues could mean that many of your customers never see this offer. Instead of boosting sales, your email sits unread in a spam folder.

Beyond the financial impact, email deliverability issues can also harm your reputation with email service providers. If your emails consistently end up in spam folders or are marked as unwanted, it becomes increasingly difficult for any of your messages to reach the intended recipients. This creates a vicious cycle where your engagement rates drop, further affecting your deliverability and, consequently, your potential earnings.

What Affects Marketing Email Deliverability?

Sender Reputation

Sender reputation is a critical metric that internet service providers (ISPs) use to determine whether your emails should be delivered to the inbox or the spam folder.

Think of like a credit score, but for your email. Just like a good credit score means you’re trustworthy to lenders, a good sender reputation tells email services you’re a trustworthy sender.

If you’ve sent emails that people marked as spam, or if lots of your emails bounce back because addresses are wrong, your “score” goes down. This makes email services wary of letting your emails into the inbox.

Recipient Engagement

How people interact with your emails matters a lot. If most people ignore your emails, don’t open them, or never click on any links inside, email services take that as a sign your emails might not be wanted.

On the other hand, if people are actively opening and engaging with your emails, it’s a good sign you’re sending stuff they like, which can help improve your deliverability.

Learn more about email open rates and the important statistics that can help improve your email marketing in our guide.

Content Quality

What’s inside your email counts. Using too many flashy sales words, having too many links, or formatting your email in a confusing way can make email services think it’s spam.

Keep your emails easy to read and relevant to the people you’re sending them to. Avoid sounding too “salesy” or using words often found in spam emails, like “Free!” or “Act now!” Instead, focus on providing value to your readers by sharing useful information, tips, or exclusive content.

Personalize your messages to address your recipients by name and tailor the content to their interests or past interactions with your brand. This approach helps build a connection and encourages engagement without triggering spam filters.

Discover how to write and design an email copy that inspires action by exploring our article on creating effective marketing emails.

Email List Health

An email list is a list of people you’re sending your emails to. Keeping this list “healthy” means regularly checking it for email addresses that no longer exist or people who never open your emails.

Sending emails to a bunch of inactive or invalid addresses can hurt your sender reputation because it looks like you’re not paying attention to who you’re emailing.

We explain step by step how to build an email list for your business in our article, helping you connect effectively with your audience.

Authentication Protocols

Email authentication protocols are like ID badges for your emails, proving they’re really from you. Use protocols like:

These protocols help email services verify your emails aren’t pretending to be from someone else. Using these can help avoid email deliverability issues, as it reassures email services that you’re a legitimate sender.

To implement the authentication protocols, you typically work with your domain provider or email service. They often provide instructions or a setup wizard in their control panel. By adding specific records to your domain’s DNS settings, you effectively activate these protocols.

This process might sound technical, but many providers offer step-by-step guides or even customer support to help you set everything up correctly.

Implementation of Authentication Protocols by Marketers

Use of Authentication Protocols by Marketers in 2023 - a Graph by Mailmodo

Source: State of Email 2024 Report, Mailmodo

Frequency and Volume

How often you send emails and how many you send at once can affect deliverability. Bombarding people with too many emails too quickly can make you look like a spammer. It’s like if someone kept ringing your doorbell over and over—you’d probably get annoyed.

Find a balance in how often you send emails so you keep people interested without annoying them.

To determine the ideal email marketing frequency for your business, explore our guide on email cadence, where you’ll find everything you need to create a strategy that engages without overwhelming.

Email Provider

The email provider you choose to send your emails plays a significant role in your deliverability. Different providers have different reputations and deliverability rates. Some are known for high deliverability and have built strong relationships with major email services like Gmail, Yahoo, and Outlook.

These providers work hard to maintain their reputation by enforcing strict email sending practices. Choosing a reputable email provider can help ensure your emails have the best chance of reaching the inbox.

They often offer tools and guidance to help you optimize your emails for better deliverability, such as managing your sender reputation, helping with list cleaning services, and setting up authentication protocols.

Best Email Hosting Providers for Enhancing Email Trust

ProviderUser RatingBest For 
5.0BeginnersVisit HostArmada
4.8Affordable PlansVisit FastComet
4.6Ease of UseVisit Hostinger

How To Check the Email Deliverability of Your Business?

Ensuring your emails actually reach your audience’s inboxes is key to successful communication. Here’s how to conduct an email deliverability check for your business:

1. Perform an Email Deliverability Audit

An email deliverability audit involves using specialized testing tools that send your emails to various controlled accounts across different email providers. Tools like Mail-Tester, Sender Score, and MXToolbox are examples of services that perform these tests.

This process helps you understand where your emails are landing: in the inbox, spam folder, or not delivered at all. This insight is crucial for identifying deliverability issues.

2. Analyze Your Email Campaign Metrics

Monitoring email marketing metrics like open rates, click-through rates, and bounce rates is essential for your email campaign success.


A decrease in open rates or an increase in bounce rates can signal email deliverability problems.

Email bounce rate shows the proportion of emails that didn’t make it to the recipient’s inbox successfully.

A high bounce rate can be a strong indicator of email deliverability problems. Within bounce rates, there are two main types to be aware of:

  • Hard Bounces: Hard bounces happen when an email is definitively refused due to the email address being incorrect or the domain no longer existing. This could be due to a typo in the email address or if the email address was deleted by the owner. Hard bounces are critical alerts that the email cannot be delivered, no matter how many attempts you make. Removing these addresses from your email list is essential to maintain a good sender reputation.
  • Soft Bounces: Soft bounces are temporary delivery failures. These can happen for a variety of reasons, such as the recipient’s mailbox being full, the email server being down temporarily, or the email message being too large. Unlike hard bounces, soft bounces do not immediately indicate that you need to remove the email address from your list, as future attempts might be successful once the temporary issue is resolved.

In addition to bounce rate, there are several other email marketing metrics relevant for tracking deliverability, which will be listed below.

  • Open Rate: Open rate refers to the proportion of recipients who have opened your email compared to the overall number of successfully delivered emails. A high open rate indicates that your emails are engaging and relevant to your audience, which can positively impact deliverability.
  • Click-Through Rate (CTR): CTR measures the ratio of recipients who clicked on any link or call-to-action in your email against the total emails that were actually delivered. A high CTR indicates that your emails are compelling and driving action, which can also positively influence deliverability.
  • Spam Complaint Rate: The proportion of recipients who reported your email as spam compared to the overall quantity of emails that reached their destination.
    A high spam complaint rate can harm your sender reputation and lead to email deliverability issues.
  • Unsubscribe Rate: Indicates the percentage of recipients who chose to unsubscribe from your email list after receiving a specific email, relative to the total number of emails that were delivered. While not directly related to deliverability, a high unsubscribe rate may indicate that your emails are not meeting recipients’ expectations, which can indirectly impact deliverability over time.
  • Delivery Rate: Delivery rate refers to the proportion of emails that successfully reached recipients’ inboxes compared to the total number of emails dispatched. A high delivery rate indicates that your emails are effectively reaching your intended audience, though it does not essentially mean they have reached their main inboxes.

These metrics are usually accessible through your email marketing platform and provide a direct look into your campaign’s performance.

3. Check Your Sender Reputation

Your sender reputation influences your email deliverability significantly. Tools offered by major email platforms, such as Google’s Postmaster Tools, can help you gauge your reputation. A low score here could mean it’s time to improve your email sending practices.

Use of Google Postmaster Tools by Marketers in 2023 - a Pie Chart by Mailmodo

Source: State of Email 2024 Report, Mailmodo

4. Conduct Regular Email List Cleanups

Maintaining a clean email list is fundamental for avoiding deliverability issues. By removing unengaged or invalid addresses, you ensure your emails are sent to interested and active users, which enhances your deliverability rates.

5. Request Feedback Directly from Subscribers

Incorporating a simple request in your emails for subscribers to notify you if they find your messages in their spam folder can offer direct feedback on your email deliverability. This hands-on email deliverability check can uncover issues you might not detect through metrics alone.

Marketing email requesting feedback - example from Similarweb

An example of a marketing email from Similarweb that requests feedback from recipients

What Is a Good Email Deliverability Rate?

A good email deliverability rate is key to ensuring your messages reach your audience. This rate measures the percentage of your sent emails that successfully land in the recipients’ inboxes, avoiding filters that would send them to spam or block them entirely.

According to the email deliverability test performed by Email Tool Tester across a variety of popular email service providers, the average deliverability rate tends to be between 83% and 89%.

Any number above 89% is considered a good email deliverability rate, with figures above 93% being excellent.

Industry benchmarks suggest that a deliverability rate above 89% is considered good. This means that out of every 100 emails sent, at least 89 should reach the inbox.

Good Email Deliverability Rates

Rates below 80% mean you should improve your email deliverability. Falling below this threshold can indicate email deliverability issues, signaling that it’s time to review and adjust your email strategies.

How Is the Deliverability Rate of Marketing Emails Calculated?

The deliverability rate of marketing emails is calculated by dividing the number of emails successfully delivered to recipients’ inboxes by the total number of emails sent, then multiplying by 100 to express it as a percentage.

The formula for calculating the deliverability rate is:

Email Deliverability Formula

For example, if you sent 1,000 emails and 900 of them were successfully delivered to recipients’ inboxes, the calculation would be:

Deliverability Rate = (900/1000) x 100 = 90%

This means that 90% of your emails reached the intended recipients’ inboxes, while the remaining 10% may have bounced, been marked as spam, or encountered other delivery issues. Calculating and monitoring your deliverability rate is essential for assessing the effectiveness of your email campaigns and identifying areas for improvement.

How To Improve Email Deliverability?

To enhance your email deliverability rates, it’s essential to address the factors influencing them.

5 Key Areas of Email Deliverability Improvement

Begin by focusing on five key areas:

  1. Ensure the quality of your email list. Regularly clean your email list to remove invalid or inactive addresses, ensuring you’re reaching engaged subscribers.
  2. Keep the level of your email content and engagement high. Create relevant and engaging content to encourage recipients to open and interact with your emails.
  3. Improve your email-sending practices: Optimize your sending frequency, timing, format, design, and mobile usability to avoid overwhelming recipients and reduce the likelihood of being marked as spam.
  4. Implement Authentication Protocols. Use SPF, DKIM, and DMARC to authenticate your emails and build trust with email service providers.
  5. Build a good sender reputation. Maintain a positive sender reputation by adhering to best practices, minimizing spam complaints, and avoiding getting blacklisted.

In the following sections, we’ll provide detailed best practices to help you improve each of these areas and enhance your email deliverability.

Email Deliverability Best Practices: 17 Proven Tips

1. Don’t Buy Email Lists

Purchasing email lists is a practice that might seem like a shortcut to expanding your audience, but it comes with significant risks that can severely damage your email marketing efforts in the long run. When you buy an email list, you are acquiring a collection of email addresses from individuals who have not agreed to receive communications from you.

This lack of consent is not just a matter of etiquette; it’s a fundamental issue. Sending emails to people who haven’t opted in can lead to high unsubscribe rates and spam complaints. Such negative feedback can harm your sender reputation. Instead of buying email lists, focus on building your list organically.

2. Maintain List Hygiene

Regularly clean your email list by removing inactive or invalid email addresses. By regularly purging inactive or invalid email addresses from your list, you guarantee that your messages are delivered to subscribers who actively engage and are interested in your content.

3. Avoid Emailing Repeat Bouncers

When an email bounces, it means it couldn’t be delivered to the recipient’s address, often because the address is wrong or no longer exists. Continuously sending emails to these addresses can make email providers think you’re sending spam, hurting your ability to reach people’s inboxes.

4. Use Double Opt-In

Double opt-in is a two-step process where a person first signs up for your email list, usually on your website, and then confirms their subscription through a follow-up email.

For example, after entering their email on your site, they’ll get an email asking them to click a link to verify they really want to receive emails from you. This makes sure your subscribers genuinely want your emails, reducing spam complaints and helping your emails get delivered properly. Send emails only to users who want to receive them.

Email Deliverability - Cluster: Email Marketing - Ela

Source: Foundations of Email Privacy, Litmus

5. Segment Your Email List

Segment your email list based on demographics, preferences, or past interactions. By sending targeted and relevant content to specific segments of your audience, you can improve engagement and reduce the risk of your emails being marked as spam.

6. Verify the Email Address You’re Using for Marketing

Verify the email address you use for sending marketing campaigns using email verification tools. This ensures it’s recognized as valid, reducing bounce rates and safeguarding your sender reputation.

You can use tools like NeverBounce, Hunter, or Mailgun for this purpose. These services check your sending email address against various databases to ensure it’s valid and not blacklisted, helping maintain your email deliverability. Simply sign up, enter your email address, and they’ll handle the verification process for you.

7. Don’t Use a No-Reply Email

Sending emails from a no-reply address can discourage engagement and may lead to higher spam rates. Using a reply-to address invites feedback and questions, making recipients feel valued and fostering a two-way conversation, whereas no-reply addresses can seem impersonal and deter interaction. Always encourage communication.

8. Optimize Email Design and Formatting

Ensure that your emails are well-designed and optimized for different devices and email clients. Use clear fonts and layout, appropriate images, clear and concise formatting, and a responsive design to enhance readability and encourage interaction with your emails.


You might find it beneficial to explore our article on email marketing design best practices to learn more.

9. Avoid Sending Attachments

Sending emails with attachments can often trigger spam filters, as these are commonly used by malicious senders to distribute harmful software. Instead of attaching files directly, consider using a secure file-sharing service or providing a link to the document hosted on a trusted platform. This approach reduces the risk of your email being marked as spam and ensures your recipients can safely access the files you’re sharing.

10. Make Unsubscribing Easy

Include a clear and easy-to-find unsubscribe link or button in your emails. Making it difficult to unsubscribe can lead to complaints and harm your reputation.

Unsubscribe Button Example

Example of a well visible unsubscribe button in an email from Stripo

11. Consider TLS Email Encryption

TLS, or Transport Layer Security, is a widely adopted security protocol designed to facilitate privacy and data security for communications over the Internet. It encrypts the data transmitted, ensuring that emails cannot be intercepted by unauthorized parties while they are in transit from sender to receiver. This layer of encryption is crucial for protecting sensitive information against eavesdropping and tampering, thereby preserving their confidentiality.

TLS is like a secure envelope for your emails. It scrambles the information you send over the Internet so only the intended recipient can read it. This stops others from snooping on your emails while they travel from you to the person you’re emailing, keeping your messages safe and private.

Implementing TLS for email encryption is often a straightforward process, typically managed by your email service provider or IT department. To get started, you’ll need to ensure that your email server and the servers of your recipients support TLS.

Most modern email systems come with TLS support by default, but it’s essential to verify that it’s enabled and configured correctly. In some cases, you may need to consult with your email provider or refer to their documentation to ensure that TLS is actively protecting your emails. It’s also wise to regularly review and update your TLS settings to align with the latest security standards, ensuring the highest level of protection for your email communications.

12. Mange Your Volume and Sending Time

Adjust the frequency and timing of your emails based on subscriber preferences and behavior. Over-mailing can lead to list fatigue and under-mailing can make subscribers forget you.


Experts usually agree it’s best to send one or two emails a week. This keeps people interested without annoying them. You should send at least one email a week, whether it’s for updates, deals, or news. If you send less often, people might forget about you or lose interest.

13. Monitor Sender Reputation

Keep an eye on your sender reputation, including the reputation of your sender IP address. Tools like Sender Score and Google Postmaster Tools are excellent resources for this purpose. These platforms provide insights into your email sending practices, identify potential deliverability issues, and help you understand how email service providers view your emails.

Address any issues promptly to maintain a positive reputation and ensure optimal deliverability of your emails. A poor reputation can lead to your emails being blocked or filtered as spam.

14. Choose Between Shared and Dedicated IP Addresses

When choosing between a shared and a dedicated IP address for your email campaigns, consider your sending volume and reputation management needs.

  • A shared IP address is typically suitable for businesses with lower sending volumes and those just starting out, as it allows them to benefit from the established reputation of the shared IP.
  • A dedicated IP address is ideal for businesses with higher email volumes and those seeking to have full control over their sender reputation, as it directly reflects their own sending practices.

15. Set Up and Follow Up On An Abuse Reporting Mailbox

Implement an mailbox to handle complaints and feedback on your emails. This dedicated mailbox serves as a direct channel for recipients to report unwanted emails, spam, or other issues directly related to your email activities. For instance, if a recipient feels they’ve received an email in error or wishes to report a perceived misuse of their email address, they can easily contact you through this channel.

By actively managing this mailbox, you demonstrate your commitment to respecting your subscribers’ preferences and upholding high email communication standards.

16. Follow Up On Anti-Spam and Privacy Regulations

Stay informed about anti-spam and privacy laws in the regions you are sending emails to, such as GDPR in Europe or CAN-SPAM in the US. Compliance is crucial to avoid legal issues and build trust with your subscribers.

17. Test and Experiment

Experiment with different email sending frequencies, send times, subject lines, and content formats to identify what resonates best with your audience. Regular testing and optimization help improve engagement and deliverability over time.

Best Email Deliverability Tools

Navigating the complex world of email deliverability requires the right tools. Here are three essential tools that cater to various needs, from small businesses to large enterprises, ensuring your emails reach their intended inboxes.


Mailgun Email Deliverability Services

Best for: Developers and businesses looking for scalable email delivery solutions.

Main Features:

  • Detailed analytics for tracking email performance.
  • Email validation to ensure accuracy and reduce bounces.
  • Advanced routing options for customized email handling.
  • API-driven service for seamless integration with applications.
  • Automated sending, receiving, and tracking of emails.
  • Provides dedicated IP addresses for reputation management.

Price Range: Starts with a free tier for up to 5,000 emails per month for the first three months. Paid plans from around $35 per month, scaling with more features and higher email volumes.

Twilio SendGrid

Twilio SendGrid Email Delivery Tools

Best for: Beginners and users seeking an easy-to-use platform for both marketing and transactional emails.

Main Features:

  • Intuitive email builder and vast template library for easy creation of emails.
  • Comprehensive marketing tools for managing campaigns.
  • Robust API for developers looking for custom integrations.
  • Deliverability optimization to ensure emails reach the inbox.
  • Real-time analytics for tracking email performance.
  • Option for a dedicated IP address to improve sender reputation.

Price Range: Starts with a free plan allowing up to 100 emails per day. Paid plans begin at approximately $19.95 per month, including advanced features and higher sending limits.

Validity Everest

Validity Everest Email Delivery Platform

Best for: Large companies and marketers focused on maximizing email deliverability and protecting sender reputation.

Main Features:

  • Comprehensive email deliverability and performance monitoring.
  • Detailed insights into sender reputation and inbox placement rates.
  • Tools for identifying and resolving deliverability issues.
  • Advanced analytics for tracking engagement and recipient behavior.
  • Access to a wide range of data on ISPs, email clients, and global sending practices.

Price Range: Customized pricing based on business needs; contact Validity Everest directly for a quote. Catered to businesses with significant email volumes and budgets.

Final Word: Better Email Deliverability Means Higher Revenues

Understanding email deliverability is crucial for any business using email marketing. Simply put, if your emails reach the inbox, you’re more likely to see better results, like more sales and higher profits. Paying attention to deliverability metrics and following best practices directly boosts your company’s earnings and return on investment (ROI).

When emails don’t get delivered, it’s a missed opportunity and a waste of effort. But when they do, each email can lead to more customers and more money. So, making sure your emails are delivered well is not just about avoiding spam folders; it’s about growing your business.

Next Steps: What Now?

Learn More About Email Marketing

Frequently Asked Questions

What is standard email deliverability?

Standard email deliverability refers to the rate at which your emails successfully reach recipients’ inboxes without being filtered into spam or other folders. Industry benchmarks suggest that a deliverability rate above 89% is considered good. Factors like sender reputation, email content, and authentication protocols influence email deliverability.

Does DKIM help with deliverability?

Yes, DKIM (Domain Keys Identified Mail) helps with email deliverability by adding a digital signature to your emails. This signature verifies that the email was sent by the domain it claims to be from, enhancing trust with email service providers. Implementing DKIM can improve your sender reputation and reduce the likelihood of your emails being marked as spam.

What is a bad email delivery rate?

A bad email delivery rate typically falls below 80%. Rates below this threshold indicate that a significant portion of your emails are not reaching recipients’ inboxes. This could result from factors like poor list hygiene, spam complaints, or inadequate authentication protocols. It’s essential to address these issues fast to improve deliverability.

Does email deliverability include spam?

Yes, email deliverability includes avoiding being marked as spam. It’s about ensuring your emails reach recipients’ inboxes and aren’t filtered into spam folders. High deliverability means your emails are successfully reaching your audience, while low deliverability can result in emails being flagged as spam and not seen by recipients. So, avoiding spam is a crucial part of email deliverability.

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