Email Deliverability: Your Full Guide

In today’s competitive digital landscape, email deliverability is critical for any organizations that rely on email to communicate, educate or sell their products.

But email communications only work if your messages land in recipients’ inboxes rather than their spam folders.

That’s where understanding and improving email deliverability is crucial, as organizations that consistently prioritize email deliverability can expect better results from their email activity.

This guide is here to demystify email deliverability best practices, equip you with the tools to run an email deliverability test, and help you optimize your email security.

Here’s what we’ll explore:

• What Determines Email Deliverability?
• How to Test Email Deliverability Through the Right Tools
• The Major Email Deliverability Best Practices
• Improving Domain and Email Sender Reputation for Better Email Deliverability
• How to Perform an Email Reputation Check
• A Step Closer: DMARC Policy and Why You Should Care
• Next Step: Checking Your DKIM Record
• SPF Record: Does It Improve Email Delivery and Reputation?
• SMTP: What It Is and How It Works
• Email Blast: Increasing Your Email Deliverability Can Make the Difference
• Pro Tip: GDPR Compliance for Your Email List
• Empower Your Email Deliverability with Simplelists

Email deliverability is the measure of how effectively your emails land in inboxes.

There are a number of factors that determine email deliverability.

A critical one is your email sender reputation, which is a trust score assigned by email providers. This reputation is shaped by your sending behavior, including bounce rates, spam complaints, and user engagement.

Another key element in email deliverability is email authentication. Implementing protocols like SPF records, DKIM authentication, and a robust DMARC policy allows email providers to verify your domain and messages as legitimate.

Email engagement also plays an important role. Email providers monitor how recipients interact with your emails — high open and click rates signal relevance and trustworthiness, while frequent unsubscribes or low engagement can negatively affect deliverability.

The quality of your email content matters too. Spam-like language, broken links, or poorly formatted designs can raise red flags with spam filters, especially when combined with inconsistent sending patterns.

Maintaining a clean email list is equally important. Invalid or inactive addresses can increase bounce rates, while disengaged users hurt your engagement metrics.

Crafting the perfect email campaign takes time and effort, from writing compelling content to designing visually engaging layouts.

But even the best-crafted emails can fall short if they never make it to your audience’s inboxes. This is where email deliverability tools become essential.

Platforms like Send Forensics and GlockApps can help you understand your inbox placement, spam filtering, and authentication results.

For instance, GlockApps can show where your emails land — whether it’s the inbox, spam folder, or blocked outright — giving you the chance to refine your strategy.

Tools like NeverBounce play a critical role in maintaining list hygiene by removing invalid or inactive email addresses, reducing bounce rates, and protecting your reputation.

Meanwhile, Litmus ensures your emails are optimized across various devices and platforms, allowing you to deliver a consistent user experience.

By using the right tools, you can address technical issues, maintain a strong email sender reputation, and ensure your emails reach their intended recipients.

Achieving consistent email deliverability requires alignment with proven best practices.

Setting up protocols like SPF records, DKIM, and DMARC policies ensures your emails are verified as legitimate, reducing the risk of them being flagged as spam. These measures not only protect your domain from spoofing but also enhance your email sender reputation over time.

Equally important is maintaining a clean, opt-in email list. High bounce rates or complaints from disengaged recipients can harm your domain reputation and negatively impact email deliverability.

Personalization and segmentation are also crucial for driving engagement.

By tailoring your emails to align with recipients’ preferences, you’re more likely to achieve higher open and click-through rates — key metrics that signal relevance to email providers.

Consistency is another vital element. It’s best to avoid sudden spikes in email volume, as this can appear suspicious to service providers. Instead, maintain a steady sending schedule to build credibility and gradually increase email volume over time.

Additionally, crafting high-quality content that avoids spam-triggering language and provides real value to recipients helps establish a positive rapport with both users and email providers.

Your email sender reputation plays a pivotal role in ensuring the success of your campaigns.

It’s essentially a trust score assigned by email providers to your domain and IP address, based on your sending history and behavior.

A strong sender reputation builds credibility, ensuring your messages consistently land in inboxes, while a poor reputation can lead to emails being flagged as spam — or blocked entirely.

Improving your sender reputation starts with proactive management.

This includes authenticating your emails with SPF, DKIM, and DMARC protocols, maintaining a clean and engaged email list, and avoiding practices like sending to outdated or purchased contacts.

Monitoring tools can also provide real-time insights into your domain and IP’s standing, helping you identify and address issues like blacklisting or sudden dips in deliverability. For example, regular DMARC checks can help ensure your authentication protocols are functioning correctly.

Looking for tips on how to improve your sender reputation? We discuss this in detail in our dedicated article:

So how do you find out whether your sender reputation is good, or needs improving?

Let’s take a look at some of the main tools you’re able to use to get the actionable insight you need.

Sender Score offers a simple 0–100 rating based on your domain’s sending history, helping you understand your standing at a glance.

Google Postmaster Tools provides insights specifically for Gmail users, highlighting issues like spam rates and authentication failures.

Other platforms, like Talos Intelligence and Cyren IP Reputation, can identify whether your domain or IP address is blacklisted, which can significantly impact your ability to reach inboxes.

But monitoring your reputation is only part of the solution.

Ultimately, your reputation is shaped by every email you send.

Regular email deliverability tests and reputation monitoring should be part of your ongoing strategy to ensure consistent inbox placement.

With proactive management and the right tools, you can optimize your email campaigns for better engagement and long-term success.

With phishing attacks accounting for 90% of cyberattacks and email fraud costing businesses millions each year, securing your domain is no longer optional — it’s essential.

This is where a DMARC policy (Domain-based Message Authentication, Reporting, and Conformance) becomes a game-changer.

A DMARC policy builds on SPF records and DKIM authentication to provide a comprehensive approach to email security.

DMARC verifies whether incoming messages align with the domain’s policies and directs how unauthenticated emails should be handled.

Implementing a strong DMARC policy also boosts your email deliverability by showing email providers that your domain is trustworthy. This improves your email sender reputation and increases the chances of your messages reaching recipients’ inboxes.

Without DMARC, your domain is vulnerable to exploitation by malicious actors, which can result in lost trust, and reduced email deliverability.

How to Create a DMARC Record

The process of how to create a DMARC record begins with accessing your domain’s DNS settings, where your DMARC record will be added as a TXT entry.

Before you get started, it’s important to make sure you’ve already configured SPF records and check DKIM authentication, as DMARC works alongside these protocols to create a layered security system.

Next, you’ll need to determine your DMARC policy level.

If you’re just starting out, a monitoring policy (p=none) is recommended. This allows you to collect data on unauthenticated emails without affecting email flow.

As your understanding grows, you can transition to stricter policies like quarantine (p=quarantine), which diverts suspicious emails to spam folders, or reject (p=reject), which blocks unauthenticated emails entirely.

You’ll also need to decide how to handle DMARC email security reports. Setting up a dedicated email address for these reports helps you stay organized while gaining valuable insights into your domain’s email-sending activity.

DMARC vs. DKIM: What’s the Difference?

When it comes to securing your email communications, DMARC and DKIM (DomainKeys Identified Mail) are two essential protocols that play distinct yet complementary roles.

While both are crucial for email security and improving email deliverability, they serve different purposes in the authentication process.

DKIM works by attaching a unique digital signature to each email you send. This signature verifies that the email’s content has not been tampered with during transit and confirms that the message originated from an authorized domain.

DMARC, on the other hand, builds upon your DKIM records, aligning their results with your domain’s policies.

DMARC lets domain owners dictate how unauthenticated emails should be handled — whether they’re monitored, quarantined, or outright rejected.

By implementing both protocols, you create a multi-layered defense system that enhances email deliverability best practices and strengthens your email sender reputation.

Checking your DKIM record involves making sure that the public and private keys are aligned, and that email providers can successfully authenticate your messages.

A misconfigured DKIM record can lead to authentication failures, impacting your ability to reach inboxes.

To verify your DKIM setup, you’ll need your domain’s DKIM selector, which identifies the specific key associated with your emails.

Tools like DNSchecker.org, MX Toolbox, and EasyDMARC make this process simple by allowing you to input your selector and domain name to check for errors or misalignments. These tools provide instant feedback, helping you identify and resolve any issues that could hinder email deliverability.

For Simplelists users, you’ll be pleased to know that enabling DKIM is seamless.

With full support for all email authentication protocols, as well as straightforward tutorials, Simplelists makes it easy to safeguard your domain and improve email deliverability.

An SPF (Sender Policy Framework) record is like a digital gatekeeper for your email communications. It specifies which mail servers are authorized to send emails on behalf of your domain.

When an email is sent, the receiving server compares the sender’s IP address with the list of authorized IPs in your SPF record.

If there’s a match, the email is authenticated and delivered. If not, it’s flagged as suspicious or rejected outright. This crucial process helps prevent spoofing and phishing attempts, safeguarding your domain and your recipients.

By setting up an SPF record, you enhance your domain’s credibility, significantly improving your email deliverability.

Authenticated emails are more likely to land in inboxes because email providers recognize them as trustworthy. On the other hand, failing to configure SPF can lead to your emails being marked as spam, blocked entirely, or exploited by malicious actors impersonating your brand.

While SPF alone is a robust tool, it’s most effective when combined with DKIM and DMARC protocols.

Together, these systems create a layered approach to email authentication, offering comprehensive protection for your domain and boosting deliverability.

Behind every email sent lies a sophisticated system ensuring your message reaches its intended recipient.

At the heart of this process is SMTP (Simple Mail Transfer Protocol), the technology that acts as the digital postal service for email communication.

Without SMTP, your emails would have no reliable way of traveling from your email client to the recipient’s inbox.

When you send an email, your email client connects to an SMTP server. This server checks the email’s details, including the sender, recipient, and content.

It then routes the message through a network of servers until it reaches its final destination. Along the way, SMTP verifies the sender’s identity and ensures that the email complies with the necessary authentication protocols, such as SPF records, DKIM, and DMARC policies.

Businesses often face a choice between using third-party SMTP email services or managing their own SMTP servers.

While third-party providers offer robust infrastructure, high deliverability rates, and advanced analytics, running your own server provides greater control but requires ongoing maintenance and expertise.

Simplelists simplifies the complexities of SMTP by offering integrated solutions designed to maximize email deliverability and security.

With features like automated bounce handling and seamless domain setup, Simplelists ensures your emails reach inboxes without the technical headaches.

Email marketing remains one of the most effective tools for businesses, offering an impressive ROI of $36 for every $1 spent.

Whether you’re sending personalized campaigns or automated sequences, email is a direct line to your audience.

Among the various strategies available, the email blast — a single message sent to a large audience — remains a debated yet powerful method when used effectively.

The strength of an email blast lies in its ability to quickly reach a wide audience. For time-sensitive promotions, urgent updates, or significant announcements, this approach ensures maximum exposure with minimal effort.

It’s cost-effective, requiring only one email to be created and sent, and it provides measurable results through metrics like open rates, click-through rates, and conversions.

However, modern consumers increasingly expect personalization and relevance in their inboxes. Traditional email blasts, which lack segmentation, can struggle to meet these expectations. Sending generic content may lead to disengagement, unsubscribes, and even spam complaints, potentially harming your email sender reputation and email deliverability.

To maximize the effectiveness of an email blast, it’s essential to follow best practices.

Start with a powerful subject line to grab attention, and optimize your email design for mobile devices, as over 40% of users check their email on smartphones. While personalization may be limited, including even basic details like the recipient’s name can improve engagement.

Timing is also critical. Avoid overwhelming subscribers with frequent emails and test the optimal time of day for your audience to increase open rates. Consistent, thoughtful email scheduling reduces the risk of spam complaints and helps build trust.

Platforms like Simplelists make managing email blasts straightforward and efficient. With robust support for SPF records, DKIM, and customizable HTML templates, Simplelists ensures your campaigns are secure, professional, and effective.

With the introduction of the General Data Protection Regulation (GDPR) in 2018, the landscape of email marketing was transformed.

Designed to protect the personal data of EU citizens, GDPR ensures transparency, consent, and accountability in how businesses manage information.

GDPR compliance applies to all forms of personal data, including email addresses, names, and even IP addresses.

One of the key changes it brought in for email marketers is the need for explicit consent to receive emails. Pre-checked boxes or vague agreements no longer suffice — subscribers must take clear, affirmative action to join your list.

Additionally, businesses must document when, how, and why consent was given, ensuring full traceability in case of audits or disputes.

Another cornerstone of GDPR is the right to opt out. Subscribers must be able to withdraw their consent easily, whether through a visible unsubscribe link or an email preference center.

While compliance may seem complex, it does come with significant advantages.

A GDPR-compliant email list is often cleaner and more engaged, with higher open rates and fewer unsubscribes. By prioritizing data privacy, you build trust with your audience, leading to stronger customer relationships and improved email deliverability.

Simplelists helps you streamline GDPR compliance, offering secure opt-in forms, automated unsubscribe handling, and data deletion features.

Improving your email deliverability demands a strategic approach backed by robust tools and best practices.

From safeguarding your domain with SPF records, DKIM, and DMARC policies to maintaining an engaged, GDPR-compliant subscriber list — every detail matters.

That’s where Simplelists can help.

Simplelists simplifies the complexities of email authentication and management, enabling businesses to focus on meaningful communication without worrying about technical roadblocks.

With built-in support for email security protocols, Simplelists ensures your emails are authenticated and trusted by providers, reducing the risk of being flagged as spam.

Whether you’re managing email blasts, newsletters, or personalized campaigns, Simplelists offers features designed to optimize your email efforts.

Sign up for a free one month trial of Simplelists and discover how easy it is to take your email deliverability to the next level.