Maximizing Email Deliverability: Strategies and Best Practices

Email Deliverability: The Essential Milestone

At its core, email deliverability refers to the ability of an email to successfully land in its recipient's inbox. Understanding its nuances is crucial for any successful email marketing strategy since deliverability is not just about avoiding spam filters—it’s also about ensuring recipients actively engage with the emails you send.

To fully understand this concept, it is important to distinguish between mere email delivery and deliverability. Email delivery refers to whether an email was successfully sent to the recipient’s email server. This doesn’t necessarily mean the email reaches the inbox or the intended recipient. 

Deliverability, on the other hand, goes a step further. Not only does it ensure that the email avoids bouncing, but it also ensures that it lands in the inbox rather than being flagged as spam.

For instance, an email might successfully reach the recipient’s email server (email delivery) but still be rejected by a spam filter and end up in the spam folder. In such a case, the email was delivered but not deliverable, so deliverability is not achieved. 

This filtering process often evaluates specific factors related to the sender, such as a poor reputation or high bounce rates, as well as characteristics of the message itself, like spam triggers or certain keywords. Email Service Providers (ESPs) use some of these signals to categorize emails based on their purpose. For example, promotional emails might be sorted into a 'Promotions' folder, while malicious or suspicious emails are blocked entirely.

Source: Everlytic.com

‍

Why Email Deliverability Matters?

Email deliverability is a critical metric for email marketers, digital marketing professionals, and business owners focused on optimizing their email campaign performance. 

After all, if email is your primary channel for reaching (potential) clients, every message that fails to reach the inbox could represent a missed sales opportunity. In fact, studies show that a deliverability rate of 84.8% for 1 million emails can result in up to $15,000 in lost revenue!

However, your campaign’s ROI is only part of the equation. Poor deliverability can have far-reaching consequences, such as your domain being blacklisted, which severely limits the effectiveness of this channel in driving your business forward.

Furthermore, removal from a spam hosting list can take up to four weeks and doesn’t instantly restore your domain’s reputation. In other words, your deliverability—and your ability to connect with your audience—will remain impaired for some time still.  

In brief, achieving high email deliverability (rates above 89%) is essential for succeeding in business in the digital era. Research shows that strategic direct mailing campaigns can deliver an ROI of up to 112%, outperforming most other forms of media marketing.

However, if your emails fail to reach their recipients' inboxes, even the best campaigns lose their potential impact. Therefore, let’s delve deeper into email deliverability’s nuances: from elements influencing deliverability to the best practices to improve it.

‍

Key Factors Affecting Deliverability

Several critical factors determine whether your email lands in the inbox or ends up in the spam folder. Understanding and managing them helps you improve email deliverability and, in turn, enhance communication with your clients. 

Email Validation and Its Role in Deliverability

Email validation is the process of verifying an email address before sending a message to it, to make sure it is valid, active, and that it can receive messages. It plays a pivotal role in enhancing email deliverability by reducing bounce rates, strengthening engagement, and avoiding spam traps, thus improving sender reputation.

To validate an email, most validation tools (like Abstract's email validation API) verify:

• Email syntax. In other words, that the email address is properly formatted.
• DNS. Thus, they confirm the existence of the domain.
• SMTP. This helps to determine if the mailbox is deliverable.

These tools also can check your email list against known bad domains, validate email address formats, verify domain validity, and even check individual mailboxes in some cases. Incorporating such a service into your email campaign process is a straightforward way to improve deliverability.

Another option, to prevent invalid emails from entering your list from the start, is integrating real-time email validation into your sign-up forms. This step can involve simple format checks, domain validation, and even real-time pinging of email servers to verify mailbox existence without sending an email.

Importance of Sender Reputation

Sender reputation is another vital component of email deliverability. Basically, it implies that ISPs (Internet Service Providers) and email services monitor the behavior and practices of senders to establish whether their emails should be delivered to the inbox. In other words, “sender reputation” refers to an email sender's trustworthiness, as evaluated by ISPs.

Factors that influence sender reputation include the volume of emails sent, how many recipients mark an email as spam, and the sender's adherence to email marketing best practices. The higher the sender reputation, the likelier is that an email will reach its recipient’s inbox. On the contrary, low sender reputation usually leads to emails being categorized as spam or blocked.

More in detail, metrics that are used to measure sender reputation include:

• Inbox placement vs. spam folder placement. Whether the recipient leaves an email in the spam folder (which deteriorates their reputation) or moves it from spam to the inbox (which improves reputation).
• Opening rates. Having a high open rate signals that an email has been found relevant and trustworthy by its recipient. Low opening rates may indicate that the emails are not interesting for their audience, suggesting poor targeting or, even, spam… Which negatively affects sender reputation.
• Click rates. Whether recipients engage with links within emails. Higher engagement equals a higher reputation, and vice versa.
• Bounce rates. When emails are sent to invalid or non-existent domains, they bounce. ISPs consider this a signal of poor list hygiene or of bought contact lists. This reduces sender reputation, making it even harder for their emails to reach the inbox.
• Complaint rates. Emails marked as spam or junk send negative signals to ISPs, harming sender reputation. Often, a single complaint per 1000 emails is enough to severely damage it.
• Unsubscribe rates. Though not as harmful as complaint rates, frequent unsubscribes can affect sender reputation since they indicate unwanted content and poor list hygiene. 

To uphold a positive sender reputation, it is important to adhere to best mailing practices. This includes adhering to ISPs’ guidelines, implementing authentication protocols, and regularly validating email addresses to keep contact lists clean. Sending targeted, personalized emails and gradually increasing the sending volume can help avoid being flagged as spam.

Authentication Protocols

Authentication protocols like SPF, DKIM, and DMARC help verify the sender's identity, reducing the risk of phishing and spoofing, and are crucial for deliverability. When properly implemented, they create a robust authentication framework that builds trust with ISPs improving sender reputation and email deliverability.

SPF (Sender Policy Framework), for instance, enables a domain owner to pinpoint which email servers are allowed to send emails on behalf of their domain. This is published as a DNS TXT record that is checked by a recipient’s mail server when an email is received. If there is a mismatch between the IP address of the sending server and the authorized IPs listed in the record, the email may be flagged as suspicious or even rejected. 

Though SPF strongly limits spoofing and other malicious email practices, it has one limitation. SPF authenticates the “envelope sender” (the return path) but not the “From” address that is visible to the recipients. Attackers can benefit from this when further authentication methods are not implemented.

Source: https://redsift.com/tools/spf-checker

‍

Source: https://www.spf-record.com/

DKIM (DomainKeys Identified Mail) uses cryptographic digital signatures to ensure an email’s content has not been tampered with during transit, reducing the chances of fraud. Additionally, this can be used to confirm the authenticity of the sender, boosting their reputation and enhancing deliverability. However, it also has a limitation: this protocol does not specify what is to be done when a signature fails to be applied or an email is unsigned. Enforcing DMARC helps to fix this.

DKIM typically involves three steps: (1) The server that sends the email includes a cryptographic signature to the email headers through a private key. (2) Said private key is rendered public for the domain, as a DNS TXT record. (3) The recipient’s sender retrieves the key to verify the signature. This ensures that the content is intact and verifies that it was sent from the stated domain.

Source: https://www.mailreach.co/dkim-checker

‍

Source: https://glockapps.com/blog/what-is-dkim-dkim-checker/

‍

DMARC (Domain-based Message Authentication, Reporting, and Conformance) is an additional authentication protocol designed to complement SPF and DKIM by addressing their security limitations. It aligns the “From” address with the authenticated domain, ensuring that SPF and DKIM validate the same domain. Besides, DMARC is used by domain owners to define policies for handling emails that fail SPF or DKIM checks. Responses can be: none (monitor, only), quarantine (send email to spam), and reject (block emails entirely). 

In brief, DMARC not only prevents phishing attacks and domain spoofing but enhances sender reputation and builds trust with ISPs. It also provides insights on malicious activity or authentication issues, via DMARC reports. 

Source: https://dmarcly.com/blog/using-dmarc-checker-to-check-dmarc-record

Source: https://emailauth.io/what-is-dmarc

‍

Email Content

Another factor affecting deliverability is the content of the email. Depending on the format and the words used, an email can either land in the recipient’s inbox, bounce, or be flagged as spam. This is due to spam filters that crawl email content, searching specific formatting, words, and patterns that signal spammy behavior… Even though they are not unequivocal.

Bypassing spam filtering, to ensure deliverability, requires some action taking. For instance, it is important to avoid spam trigger words, misleading or incomplete subject lines, and lack of contact information, and adhere to professional formatting standards.

Frequent formatting issues that can be interpreted as spammy behavior encompass excessive capitalization and punctuation, large images with little text, broken links, and unusual fonts and colors. Not featuring a clear unsubscribe option is, also, a potential spam trigger.

On the other hand, common spammy words include: 

• Financial terms and promotions: Free, $$$, Earn $, Discount, Save, Credit, Loans, Get Paid, Free Gift Cash Bonus, 100% Free, Bank Transfer. 
• Urgency/exaggeration and guarantees: Act Now, Urgent, Don't Delete, This isn't spam, Once in a lifetime, Limited Time, Buy Now.
• Questionable content: Miracle, Promise you, Satisfaction Guaranteed, Risk-Free, No Catch, No Credit Check, Double your Income.
• Call to action: Buy, Clear, Give away, Order now, See for yourself, Click Here, Verify Your Account.
• Miscellaneous: Winner, Amazing, Cancelling won’t be easy, Confidentiality, No obligation.

List Hygiene 

Sending messages to a contact list full of unengaged, or nonexistent addresses can severely damage your sender reputation and, consequently, your deliverability. To prevent this, it is essential to keep a clean and updated list, by regularly cleansing it of invalid addresses. 

This will help you maintain a healthy sender reputation, further improving deliverability and optimizing campaigns for audience engagement and higher ROI. You can periodically run your existing email list through an email validation process, to sieve your contacts. 

This practice is essential for removing not just invalid emails but also addresses that might have become inactive over time and are potentially harmful to your deliverability—such as spam traps. After all, if your emails frequently land in spam folders, aren’t opened by their recipients, and bounce, ISPs can be triggered to throttle, filter, or block your emails entirely. If the issues persist, you can even face the risk of ending up on a blocklist.

User Engagement

When mailing campaigns are involved, “user engagement” refers to the way recipients interact with the messages they receive. Thus, it helps ESPs determine if users are interested in the content of the emails they are receiving. 

High engagement rates signal to ESPs that your content is valuable and relevant. When ESPs establish that recipients are engaged with your messages, the likelihood of your emails being delivered to the inbox grows. Conversely, low engagement can lead to your emails being filtered as spam or blocked.

User engagement indicators include: open, reply, bounce, unsubscribe, and click-through rates, as well as time spent reading, forwards and shares, and conversions. Spam folder interaction and complaints can also be analyzed as engagement metrics.

Once user engagement significantly lowers, rebuilding ESPs' trust in you can take months. Measures must aim to improve engagement in a consistent way. To achieve this, you may try re-engaging your audience or cleansing your contact list from invalid addresses and only sending emails to active users.

IP and Domain Reputation

‍IP Reputation is the trustworthiness or credibility that the IP address from which emails are sent has for ISPs. ‍Domain Reputation is similar to IP reputation but refers to the domain name from which emails are sent. Poor IP and Domain Reputation can lead to emails being blocked or filtered into spam. On the contrary, high Domain and IP reputation make it more likely that they reach the recipient’s inbox.

Factors affecting IP reputation include frequent spam complaints, high bounce rates, being caught by spam traps, and irregular sending volume and frequency. For its part, Domain Reputation is calculated based on: 

• Content quality (i. e. relevant messages that do not include spammy words).
• Usage of authentication protocols.
• Regularity of sending patterns. 
• The reputation of URLs linked within the message. 
• Recipients’ engagement (high open and click-through rates, and low unsubscribe rates).

Consequently, maintaining positive IP and Domain Reputation involves following best practices for crafting and sending emails.

How to Measure Your Email Deliverability Rate

Having good email deliverability is a critical factor for a successful email marketing campaign. To achieve this, one essential step is to monitor deliverability regularly and adjust your mailing strategy as needed. This process involves leveraging tools and techniques to test performance and accurately interpret key deliverability metrics. 

Measuring email deliverability requires tracking both engagement and technical metrics, which provide a comprehensive view of whether your emails are reaching the recipient's inbox and highlight areas for improvement. Some of those metrics are:

• Delivery rate: Indicates the percentage of emails successfully delivered to recipients’ servers. A low delivery rate may signal technical issues or poor sender reputation.  Addressing these problems typically involves checking for IP blacklisting, ensuring proper email authentication, and maintaining a clean sender reputation. Mail Genius and Litmus provide delivery rate testing features that integrate with various Email marketing platforms, helping you monitor and improve your email performance.
• Inbox placement rate: Provides a clearer measure of deliverability, as it represents the percentage of delivered emails that successfully reach the inbox. Low inbox placement rates can signal issues with sender reputation, list hygiene, or spammy content. Tools like GlockApps and Mail Genius are valuable for analyzing inbox placement and identifying areas for improvement.
• ‍‍Spam complaint rate: This metric shows the percentage of recipients who flag your email as spam. High spam complaint rates can severely impact your sender’s reputation and deliverability, potentially leading to blacklisting. Therefore, keeping this rate as low as possible is essential for a healthy email strategy. Programs like SenderScore help you monitor this metric and provide insights to prevent it from escalating.
• ‍Bounce rate: Indicates the percentage of your emails that were not delivered to the recipient's inbox. A high bounced email rate could signal issues with your email list quality or with your sender reputation. There are two types of bounces to monitor: hard bounces (permanent delivery failures) and soft bounces (temporary delivery issues). In most cases, Google Postmaster Tools are useful for tracking them.
• Open rate: While not exclusively a deliverability metric, the open rate can indirectly indicate deliverability issues. Consistently low open rates across campaigns may suggest that emails are landing in spam rather than the inbox. Many platforms such as HubSpot and Mailchimp offer integrated tools to track and analyze open rates effectively.
• Sender reputation score: It reflects your email-sending reputation. This metric is calculated based on factors such as recipient engagement, bounce rates, spam complaints, and spam traps. A low sender score typically indicates issues with technical setup, list hygiene, or audience targeting, and it often leads to reduced deliverability, as emails may fail to reach recipients' inboxes or even their servers. Tools like Mailtrack and SenderScore provide valuable insights regarding this
• Unsubscribe rate: The percentage of contacts who unsubscribe from your mailing list. Helps you determine whether your content and frequency align with your audience’s expectations. Although not a direct deliverability metric, the unsubscribe rate provides valuable insights into audience engagement—an essential factor in ensuring your emails consistently reach inboxes. Email marketing platforms such as Constant Contact and Active Campaign often include tools for tracking this.

Another technique to measure email deliverability is the usage of seed lists. A seed list is a list of email addresses used solely for testing the deliverability of your campaign. These email addresses should be spread across different email providers (Gmail, Yahoo, Outlook, etc.) to test how well your emails perform across different platforms. By sending your campaign to this list before the actual launch, you can get a good idea of where your emails are landing.

Best Practices to Improve Email Deliverability

Successfully improving your email delivery rate often requires a multifaceted approach, focusing on both technical setup and content strategy. Here are some strategies and best practices to consider.

Keeping it Clean

As mentioned above, “list hygiene” refers to the practice of regularly cleaning your email list to remove inactive, incorrect, or unengaged subscribers. Keeping your list clean minimizes bounces and improves your engagement rates, which are critical for enhancing email deliverability. Here are some effective strategies for maintaining a polished and highly engaged contact list: 

• Regular list cleaning: A good rule of thumb is to clean your email list every 3 to 6 months. However, this frequency can be adjusted depending on your email-sending volume and the rate at which you acquire new subscribers.

• Frequently remove inactive subscribers: Identify subscribers who have not engaged with your emails over a period of 6 to 12 months, and remove them from your list. Segmenting your list can simplify this process and help you run targeted re-engagement campaigns.
• Automate bounce processing: Configure your mailing platform to automatically identify and remove hard bounces, as well as soft bounces after a specified number of failed delivery attempts. Platforms like Mailchimp and SendGrid offer this feature.  
• Enable double opt-in: This method ensures that the people who subscribe to your list are genuinely interested in receiving your emails, reducing spam complaints and boosting engagement rates. It also helps prevent invalid emails from sneaking into your contact list.
• ‍Verify email addresses: Implement email verification tools to catch and correct typos at the point of sign-up and eliminate invalid email addresses, including role-based email addresses, from your list. This strategy helps you reduce bounces, safeguarding your sender reputation, and optimizing your campaign’s ROI.
• Track email list growth rate: Rapid list growth, without a growing engagement, can be a sign that you are sending emails to invalid or low-quality addresses. To avoid this, make sure, from the very beginning, that your sign-up process is focused on attracting quality leads. Also, avoid purchased lists at all costs.

Authentication Protocols: The Proper Approach

Email authentication is vital for proving that an email is not forged and comes from a legitimate source. SPF, DKIM, and DMARC are three critical authentication methods that help improve your email deliverability. We have already reviewed what are they and why they are essential in any mailing campaign. Now, let’s delve into how to configure them to achieve optimal results.

• ‍SPF (Sender Policy Framework): To set up SPF, you need to add a specific TXT record to your domain's DNS settings that lists the IP addresses allowed to send emails from your domain. To check whether your IP address is blocked, you can refer to relevant sites such as DNS Checker or WhatIsMyIP.com.‍ Understanding what an MX record is can also help in this setup.
• ‍DKIM (DomainKeys Identified Mail): To implement DKIM, you'll need to generate a DKIM key pair and add the public key as a TXT record in your DNS settings. Also, make sure that your email service provider supports DKIM signing for your outgoing emails. 
• DMARC (Domain-based Message Authentication, Reporting, and Conformance): To properly configure DMARC, you first need to set up SPF and DKIM for your email domain. Then, add a DMARC record to your domain’s DNS settings in TXT format. Once the record is in place, implement a DMARC policy. It's advisable to start with "None" (monitoring results to gather data) and gradually move to "Quarantine" or "Reject" for emails sent from your domain that fail DMARC checks.

For a better understanding, watch this video on how to set up email authentication!

How to Avoid Spam Traps

Spam traps are email addresses specifically designed to catch senders who engage in poor email list hygiene or spamming activities. However, even legitimate senders can end up emailing these addresses unintentionally and suffering the consequences. Namely, lower domain reputation and blacklisting (both of which negatively impact email deliverability), as well as legal compliance risks. 

Spam traps can be categorized as either “pristine” (addresses that have never been used by real people, created by ISPs, anti-spam organizations, or ESPs to catch spammers) or “recycled” (abandoned email addresses, deactivated by the provider and converted into spam traps). Recycled spam traps typically indicate poor email list hygiene, while pristine spam traps suggest that your mailing campaigns rely on automated processes.

Some measures you can take to prevent emailing spam traps include:

• Regularly validating your contact list, using tools such as Abstract API. This will filter out invalid, inactive, or disposable addresses. In other words, potential spam traps. Building your list organically, and avoiding purchased contact lists, also helps you bypass spam traps. 
• Gradually increasing your sending volume is essential if you are new to email campaigns, have a small contact list, or a history of low engagement and high bounce rates. This approach minimizes the risk of appearing suspicious to ISPs, reducing the chances of being flagged for hitting spam traps.
• Implementing straightforward and easily accessible unsubscribe processes helps prevent uninterested subscribers from complaining about your messages or marking them as spam. Continuing to email such recipients increases the risk of encountering spam traps and damaging your deliverability.
• Using double opt-in methods prevents bot sign-ups that could introduce pristine spam traps into your contact list. Additionally, it reduces the risk of adding invalid email addresses, which in turn helps maintain strong deliverability rates.
• Checking for spam traps using specialized detection tools (like Spamhaus), before sending out a mailing campaign. Another valuable strategy is signing up for feedback loops (FBL). Thus, you will get reports from ISPs when recipients mark your emails as spam and will be able to remove their addresses immediately.

Email Segmentation & Personalization

Effective segmentation involves dividing your email list based on specific criteria such as demographics, past purchase behavior, or engagement levels. This approach allows for more targeted and relevant email campaigns designed to boost open and engagement rates, which, in turn, enhances email deliverability. Actionable strategies include:

• Segmenting by activity, and customizing re-engagement campaigns for inactive subscribers, based on past interactions and preferences. You can even create personalized offers or discounts set up for specific dates like birthdays or anniversaries.
• Using demographics to tailor content that resonates with different groups. AI-driven analytics can identify patterns that lead to higher spam complaints or unsubscribes, allowing marketers to adjust their strategies accordingly.
• Segmenting by purchase history to send personalized product recommendations. Additionally, using AI can significantly improve email deliverability by optimizing subject lines for higher open rates, and personalizing email content for each recipient to increase engagement.

The key is to keep email personalization simple, relevant, and non-intrusive to avoid overwhelming your subscribers, especially, when dealing with inactive contacts. Using the subscriber’s name, adjusting send times to their time zone, and implementing automatic behavioral triggers increase the likelihood of opens and clicks, while also helping you avoid being flagged as spam.

The Key to a Good Name

As highlighted above, sender reputation influences whether your emails will reach the subscribers’ inboxes or their spam folders. Therefore, here are some useful tips to maintain and improve your sender reputation:

• ‍Monitor your sending volume: Avoid sudden spikes in email volume, as this can trigger spam filters. Gradually increase your sending volume over time, to avoid looking suspicious to ISPs.
• ‍Engage with active subscribers: Focus your efforts on subscribers who regularly interact with your emails, and don’t try to get back people who have already unsubscribed. High engagement rates positively affect your sender’s reputation.
• Swiftly address complaints and bounces: Remove email addresses that result in bounces and pay attention to spam complaints. ISPs track these metrics to evaluate your reputation.
• Keep track of your IP reputation to promptly detect issues that can affect sender reputation, such as engagement drops, spam complaints, high bounce rates, and blacklisting warnings.
• Use tools like Google Postmaster Tools, Microsoft SNDS, and Sender Score to gain insights into how ISPs view your sending behavior. Sign up for mailing platforms (like Mailchimp and HubSpot) that provide delivery analytics and integrate with tools for monitoring sender reputation.

Do you want to know whether your email deliverability strategies are up to the mark? Take this quiz to find out!

Common Challenges & Solutions

As mentioned earlier in this article, several factors can influence email deliverability, either positively or negatively. However, issues hindering it do not always align with them. 

Challenges to email deliverability significantly impact the effectiveness of your email campaigns. Therefore, understanding how to identify and resolve these issues is crucial for maintaining a healthy email program and ensuring compliance with legal laws.

Bouncing Back

When an email bounces, it fails to reach the recipient’s inbox. Bounces can be categorized into two types, based on the underlying causes: hard bounces and soft bounces.

A hard bounce occurs when an email is permanently rejected due to reasons such as an invalid email address or a non-existent domain. This indicates that the email cannot be delivered by any means. The best course of action is to promptly remove such addresses from your contact list, to shield your sender reputation and maintain optimal email deliverability.

On the other hand, a soft bounce occurs due to temporary issues (such as a full recipient's inbox or a server being down) indicating that the email could be delivered once the problem is solved. In most cases, attempting to resend the email a few times is sufficient to overcome soft bounces. However, if subsequent attempts continue to fail, it is advisable to remove the address from your contact list to protect your sender reputation.

Regular list cleaning, implementing double opt-in processes, using email validation tools, and leveraging automated solutions integrated into ESPs can prevent bounced emails, thus protecting your deliverability from their impact.

Spamming the Spam

There are several reasons why an email may end up in the spam folder, instead of the inbox. Gaining a detailed understanding of these factors can help you prevent such issues, ultimately safeguarding your deliverability. So, what triggers spam filters in most ESPs? Typically, it boils down to one of four common mistakes:

• Featuring content that looks spammy.
• Failing to personalize subject lines.
• Poor sender reputation and exhibiting erratic sending patterns.
• Non-compliance with email authentication protocols (SPF, DKIM, DMARC).

The good news is that these issues can be effectively addressed by:

• ‍Reviewing and adjusting your email content: Avoid using suspicious phrases (check out our list above), maintain a balanced text-to-image ratio, and personalize your emails to foster engagement with your recipients.
• Authenticating your emails: Set up SPF, DKIM, and DMARC records for your domain to verify your emails' authenticity and enhance trustworthiness.
• ‍Improve your sender reputation: Maintain a consistent sending schedule and volume. Additionally, encourage recipient engagement and regularly remove inactive addresses and bounces from your list.
• Using a reputable ESP: Partnering with a reputable Email Service Provider ESP can significantly improve your deliverability. Note that reputable ESPs often require compliance with standards, such as maintaining a higher sender score or avoiding malicious practices.

However, if your emails continue to land in spam folders, you may need to ask your subscribers to whitelist your address. You can achieve this by including a note in your emails, encouraging recipients to add your email address to their contacts. 

An alternative is providing users with whitelisting instructions, specific to each email platform. For instance, while Gmail requires users to click the three dots next to the email, and select "Add to Contacts" and Yahoo works similarly, Outlook users have to right-click on the email and choose "Add to Safe Senders".

Blacklisting

A third challenge that email deliverability faces is blacklisting, which occurs when your IP address or domain is flagged for unethical mailing practices. Blacklisted addresses are added to lists that signal to ISPs to reject emails or send them directly to spam as they are considered likely to feature malicious content.

There are several tools you can use to check if your IP or domain is blacklisted. MxToolbox Blacklist Check, for example, lets you verify your status across major blacklists, while Spamhaus provides its own blocklist search for IPs. Additionally, SenderScore helps you identify potential blacklisting by evaluating your IP score; a score below 70 may indicate you are listed.

Although being blacklisted can seem like a significant setback, it is not the end of the world. Recovery is possible and involves the following steps:

1. Identify the cause. Blacklisting doesn’t happen without reason. Begin by analyzing your metrics, focusing on spam complaints, hard bounces, and engagement rates, to establish what caused the blacklisting. Additionally, ensure that SPF, DKIM, and DMARC protocols are properly configured, as authentication issues often contribute to blacklisting.
2. Fix the problem. If poor list hygiene is the root cause, remove invalid or inactive addresses from your database. Strengthen your list quality by implementing double opt-in processes, running re-engagement campaigns, and crafting emails that resonate with your audience.
3. Request removal. Once you’ve resolved the issues, submit a removal request to the specific blacklist. Each blacklist has its process, but, generally, you’ll need to explain the steps you’ve taken to fix the problem and prevent recurrence. 
4. Be on guard: After successfully being removed from the blacklist, keep on monitoring your reputation and deliverability metrics, to make sure that the issue doesn’t recur and avoid falling back into bad practices.

Mastering Deliverability: Better Emails, Better Results

Maximizing email deliverability is essential for the success of any email campaign. With the right approach and tools, overcoming common deliverability challenges becomes manageable, leading to improved campaign performance, higher engagement rates, and stronger customer relationships. 

Ultimately, committing to best practices in email deliverability goes beyond avoiding spam folders—it's about building meaningful connections with your audience… However, no connections can be made if the addresses you are sending your messages to are invalid. This makes email verification the cornerstone of deliverability and renders validation tools a must-have.

Ready to launch your email campaigns like a pro? Then, Abstract’s Email Validation API is exactly what you need. Built by developers for developers, Abstract‘s primary goal is to deliver high-quality, comprehensive solutions designed for the world’s leading engineering teams.

Visit our website to learn more about our APIs and their benefits. Already convinced? Get your free API key, and start validating emails right away!

‍