Email deliverability is an indispensable aspect of a successful email campaign. Understanding what email deliverability is and how to boost it can completely transform the effectiveness of your email marketing efforts and ensure a strong return on investment.
The average email deliverability rate across sectors is 83.1%. As a result, nearly one in six legitimate, permission-based marketing emails never reach the intended recipient’s inbox, leading to wasted time, money, and effort on campaigns with minimal results.
What is Email Deliverability?
Email deliverability measures how many of the emails you send are accepted by internet service providers. The email deliverability rate is the number of successfully sent emails as a percentage of all the emails you send.
Email deliverability covers your message’s entire journey, from the server to the recipient’s inbox.
Why Email Deliverability Matters in Email Marketing
Email deliverability is of crucial importance for your ROI. A high email deliverability rate means that your messages are likely to be seen and engaged with by the intended recipients. Some important metrics affected by email deliverability include:
- Open rates and click-through rates: When emails reach the inbox, it’s more likely that the recipient will open and engage with them.
- Conversion rates and revenues: Higher visibility often translates into opportunities for conversions.
- Campaign effectiveness: High email deliverability means your entire email strategy performs better.
Poor deliverability can severely impact open rates, engagement, and brand reputation. When emails do not reach inboxes, it can result in:
- Decreased visibility and low engagement with your content
- Reduced ROI on email marketing efforts
- Damage to sender reputation, which can impact the effectiveness of your future campaigns
- Loss of trust from subscribers after not receiving important information on time
Key Factors Influencing Email Deliverability
There are several factors that can affect your email deliverability:
- The reputation of the sender: Your history of sending practices and recipient engagement in the past can play an important role in how ISPs treat your emails.
- Authentication protocols: The Implementation of SPF, DKIM, and DMARC can help you verify your identity and prevent email spoofing.
- Quality of your email content: Is your email relevant? Is it accurate? Does it provide value? The relevance and quality of your emails can affect your reputation, engagement, and email deliverability.
- List hygiene: Make sure your subscriber list is always up-to-date and engaged with your emails.
What is a Good Email Deliverability Rate?
The average deliverability rate is 83.1%, but it is always better to strive for more. Determining whether an email deliverability rate is good or not can be challenging, as there is not a single number that applies to all businesses, periods, and geographic locations. That being said, some general industry benchmarks and targets can give you an idea of what’s relatively better and what’s not.
- A rate above 95% is considered excellent and is what you should aim for in your marketing campaigns.
- A rate between 90-95% is good and is a sign of an effective email program.
- If your email deliverability rate is below 90%, then it’s your sign to pay more attention to the quality of your emails, your sending practices, and the overall health of your email ecosystem.
How to Measure and Improve Your Deliverability Rate
If you would like to measure and boost your email deliverability rate, you should:
- Monitor bounce rates, open rates, and spam complaints regularly to understand the state of your email ecosystem.
- Use email deliverability testing tools to simulate how different ISPs and email clients handle your messages.
- From time to time, clean your email list and remove inactive subscribers to ensure your list is up-to-date and engaged.
- Implement authentication protocols. If you’re having a hard time doing so manually, you can always make use of hosted services (e.g. hosted DMARC, hosted DKIM, hosted SPF, etc.).
Common Email Deliverability Challenges
Below are some common email deliverability challenges that senders face in their email marketing campaigns.
Spam Filters and Content-Based Filtering
Spam filters make use of complex algorithms to analyze email content, sender information, and recipient engagement. In order not to trigger these filters, you should:
- Never use spam trigger words in subject lines and content. Such words include “free,” “limited offer,” “unlimited,” “no cost,” “claim,” and numerous others.
- Keep a consistent sending volume and frequency. Try to avoid sudden spikes in email volume, as this can look suspicious to internet service providers.
- Keep your email content relevant and valuable to your recipients. Engagement metrics affect the way spam filters assess your emails.
- Use a balanced mix of text and images. Note that including too many images can trigger spam filters.
Bounce Rates and Handling Undelivered Emails
Bounces occur when emails can’t be delivered. There are two types of bounces:
- Hard bounces: These are permanent delivery failures that are due to invalid addresses or non-existent domains. These should be removed from your list immediately.
- Soft bounces: These refer to temporary issues like full inboxes or server problems. Monitor soft bounces and remove addresses that consistently bounce.
You can reduce bounce rates by taking the following steps:
- Clean your email list to remove invalid or inactive addresses.
- Make use of double opt-in to make sure only valid and relevant email addresses are added to your list.
- Monitor and remove consistently bouncing addresses to maintain list quality.
Blocklists and Their Impact on Sender Reputation
Being on a blocklist can damage your sender reputation and deliverability. Blocklists are databases of IP addresses or domains that have been flagged for sending spam or engaging in suspicious email practices. You can try to avoid blocklists if you:
- Do not purchase email lists. Only send to recipients who have truly opted in to receive your communications. Purchased lists will most often give you nothing but irrelevant, uninterested recipients. This is where “quality over quantity” should definitely be your priority.
- Monitor your sender reputation.
- Keep good email list hygiene by removing unsubscribes and bounced addresses as soon as you notice them.
- Respond immediately to user unsubscribe requests.
Sender Reputation and Domain Trustworthiness
Your sender reputation is a score assigned by ISPs based on your sending practices. To have a good reputation, you should:
- Send only relevant, engaging content that recipients want to receive.
- Keep a consistent, balanced sending behavior and avoid spontaneous, high-volume blasts.
- Encourage recipient engagement by creating valuable, interactive content.
- Address deliverability issues as soon as you detect them.
- Use a dedicated IP address for sending emails if you have a high volume of emails.
Authentication Issues and Their Role in Email Security
Email authentication helps prevent email spoofing and phishing and improves email deliverability. Try to implement these key authentication protocols:
- Sender Policy Framework: SPF is a crucial email authentication method implemented through DNS TXT records. It helps determine a list of valid, authorized IP addresses and servers permitted to send emails on your domain’s behalf. An email sent from your domain contains the IP address of the sending server and the domain’s email service provider. These details are stored in your DNS as an SPF record (you can create one with a trusted SPF generator to ensure maximum accuracy).
Once the recipient’s mail server receives your email, it conducts a verification process. The server verifies the legitimacy of the sender by comparing the IP address of the incoming email against the Sender Policy Framework (SPF) record linked to the sending domain. Based on this verification process, the email is marked as either SPF pass or fail to avoid different forms of unauthorized use.
- DomainKeys Identified Mail: DKIM refers to the standard email authentication protocol that uses a private key for assigning a dedicated cryptographic signature to validate emails in the server of the receiver. It helps to check the legitimacy and authenticity of all incoming emails. The server of the receiver can use the public key to decode the DKIM signature and see if the email has been manipulated in the transmission process or has stayed intact.
- Domain-based Message Authentication, Reporting, and Conformance: DMARC specifies how receiving servers should handle authentication failures and allows domain owners to receive reports on authentication results.
Email Delivery vs. Email Deliverability
Email delivery and email deliverability may sound quite similar, but they differ in crucial ways:
Email delivery simply means that your email is successfully delivered by your email service provider to the recipient’s incoming mail server. Email deliverability, on the other hand, covers whether or not the email reached the inbox.
Deliverability is crucial as it determines if recipients will see and engage with your message.
Delivery is mainly affected by technical issues, such as server configuration and basic authentication, while deliverability can be affected by numerous factors, such as sender reputation, content quality, advanced authentication protocols, sending frequency, blacklists, bounces, spam complaints, etc.
Best Practices to Improve Email Deliverability: Complete Checklist
Here are the best practices to help you boost your email deliverability:
Implement DMARC, SPF, and DKIM for Authentication
Email authentication protocols like DMARC, SPF, and DKIM work together to verify your identity as a sender and protect against email spoofing. When you carefully and correctly implement these protocols, you will see an improvement in not only your email deliverability but also in your overall safety and protection from phishing attacks.
Maintain a Clean and Engaged Email List
As discussed already, you should try to remove inactive subscribers who haven’t engaged with your emails in 6-12 months. You should take this action from time to time to ensure the list is always updated.
Never use purchased email lists as they can contain invalid or unengaged addresses and not bring any value to your email marketing efforts (they might in fact harm your efforts). Instead, build your own lists with effective marketing strategies (e.g., giving a free e-book to those who subscribe, giving a complimentary demo session, etc.). Use double opt-in for new subscribers so that there are no irrelevant or uninterested joiners.
Once you have the list, try to segment it based on engagement and preferences to send more targeted, relevant content.
Craft High-Quality, Non-Spammy Content
Provide valuable, informative, verified content in your emails, and try to make the information as personalized as possible. This is why understanding your target audience, their preferences, behavior, and demographics is crucial for better content and higher engagement.
Avoid sales-heavy content or a highly promotional tone, as these can push people away and make you come across as too desperate to sell your products and services.
Optimize Sending Frequency and Timing
Do not overwhelm your subscribers with too many emails. You can test different sending times to maximize engagement based on your audience’s habits.
When your sending patterns are consistent, this can help you establish predictability with recipients and ISPs and result in higher engagement.
Ensure Mobile-Friendly and Responsive Email Design
Use responsive design templates that you can adapt to different screen sizes and devices.
Also, keep subject lines concise (30-40 characters) for optimal mobile viewing. For mobile reading, try to use a single-column layout since it makes the reading experience easier and more enjoyable on mobile devices.
Avoid Spam Triggers in Subject Lines and Content
Do not use all-caps text and spam trigger words in both subject lines and email body, and refrain from excessive punctuation. Aim for a balanced text-to-image ratio with at least 60% text. Another good practice is to use alt-text for images to provide context in case some or all of the images are blocked.
Monitor and Improve Sender Reputation
Use digital tools to track your reputation. If you detect any issues, try to address them at your earliest convenience so that you can maintain a good sender score.
Use a Reliable Email Service Provider (ESP)
Choose an ESP with strong deliverability features and support. Leverage your ESP’s analytics and reporting tools along with built-in features for list management, segmentation, and automation.
Final Thoughts
Remember, good email deliverability is not about one single email getting delivered to your intended recipient’s inbox or you having a good short-term ROI from your marketing campaign. It’s about the long-term relationship between you and your subscribers, your domain and business reputation, and the long-term ROI of your email marketing campaigns.
Understanding how important email deliverability is for your long-term business success should motivate you to consistently monitor and test your email content, email sending practices, and overall email health. Additionally, you should try to be as flexible as possible and always adapt to changing trends, standards, and regulations for a relevant and attractive online presence.
- Mastering Email Deliverability: Best Practices for Successful Campaigns - March 5, 2025
- Google Calendar Spoofing: How Attackers Use It for Phishing Scams - March 3, 2025
- DNS Amplification Attacks: Examples, Detection & Mitigation - February 25, 2025