How to Improve Email Deliverability: Proven Strategies for 2026

Key Takeaways (TL;DR)

• Authentication is Non-Negotiable: To improve email deliverability, you must set up SPF, DKIM, and DMARC. These protocols prove your identity to inbox providers like Gmail and Yahoo, preventing your emails from being flagged as suspicious.
• Sender Reputation is Everything: Your sending history, IP reputation, and domain reputation determine whether you land in the inbox or spam folder. Positive engagement (opens, clicks) builds your reputation, while high bounce rates and spam complaints damage it.
• List Hygiene is Critical: Regularly clean your email list to remove invalid addresses, inactive subscribers, and potential spam traps. A smaller, highly engaged list is far more valuable for deliverability than a large, unengaged one.
• Content and Engagement Matter: Mailbox providers analyze how subscribers interact with your emails. Sending relevant, personalized content that encourages opens and clicks signals that your emails are wanted, which helps increase email deliverability.
• Warm Up New Infrastructure: If you're using a new domain or dedicated IP, you must gradually increase your sending volume. This "warming" process builds trust with inbox providers and is essential for establishing a good sender reputation.

Table of Contents

1. Proven Strategies to Improve Email Deliverability at a Glance
2. What is Email Deliverability? (And Why It's Not the Same as Delivery)
   
   1. Email Delivery
   2. Email Deliverability
3. What Affects Email Deliverability?
   
   1. Sender Reputation
   2. Email Authentication
   3. Subscriber Engagement and List Quality
4. How to Improve Email Deliverability: 12 Proven Strategies
   
   1. Set Up and Verify Email Authentication (SPF, DKIM, DMARC)
   2. Warm Up Your IP and Sending Domain
   3. Practice Rigorous Email List Hygiene
      
   4. Never, Ever Buy an Email List
   5. Personalize Content and Segment Your Audience
   6. Optimize Your "From" Name, Subject Line, and Preheader
   7. Make It Easy to Unsubscribe
      
   8. Monitor Your Sender Reputation and Blocklists
   9. Maintain a Consistent Sending Schedule
   10. Balance Your Image-to-Text Ratio
   11. Avoid URL Shorteners
   12. Ask Subscribers to Add You to Their Address Book
5. How to Fix Email Deliverability Issues
6. Let ColdIQ Handle Your Deliverability Challenges
7. Frequently Asked Questions (FAQs)

Sending a marketing email is only half the battle. All the effort you put into crafting the perfect subject line and compelling copy is wasted if your message never reaches the subscriber's inbox. Unfortunately, a significant portion of emails never do. Industry data shows that nearly 1 in 5 emails either goes to the spam folder or gets blocked entirely. This is where learning how to improve email deliverability becomes a critical skill for any marketer.

Poor deliverability not only tanks your campaign ROI but also damages your brand's reputation over time. Inbox providers like Gmail and Outlook are constantly updating their algorithms to protect users from spam, making it more challenging than ever to secure a spot in the primary inbox. This guide provides a comprehensive breakdown of email deliverability best practices for 2026, offering proven strategies to help you navigate the complexities of inbox placement and ensure your messages get seen.

Proven Strategies to Improve Email Deliverability at a Glance

What is Email Deliverability? (And Why It's Not the Same as Delivery)

Many marketers use the terms "email delivery" and "email deliverability" interchangeably, but they represent two different stages of an email's journey. Understanding the distinction is the first step to diagnosing and fixing problems.

Email Delivery

This refers to whether a recipient's mail server accepts your email. A successful delivery means the email didn't hard bounce due to an invalid address or server issue. Your delivery rate is calculated as: (Emails Sent - Bounces) / Emails Sent. Most email service providers (ESPs) report high delivery rates (e.g., 99%), but this metric is misleading because it doesn't tell you where the email landed.

Email Deliverability

This refers to where your email lands after being accepted by the server. Did it arrive in the primary inbox, the promotions tab, or the dreaded spam folder? This is the metric that truly matters. You can have a 99% delivery rate but a 50% deliverability rate if half your emails are going to junk.

In short, delivery is about getting to the door. Deliverability is about being invited inside. To increase email deliverability, you need to convince Internet Service Providers (ISPs) that you are a trustworthy sender whose messages are wanted by recipients.

What Affects Email Deliverability?

Inbox placement is not random. ISPs use a complex set of signals to score your emails and decide their fate. These factors can be grouped into three main categories: sender reputation, authentication, and subscriber engagement.

Sender Reputation

Your sender reputation is like a credit score for your email program. It's built over time based on your sending practices. ISPs track reputation at two levels:

1. IP Reputation: The reputation associated with the IP address you send from. If you're on a shared IP (common with most ESPs), your reputation can be affected by other senders on that IP. If you're on a dedicated IP, you are solely responsible for its reputation.
2. Domain Reputation: The reputation tied to your sending domain (e.g., yourbrand.com). This is becoming increasingly important, as it follows you even if you switch ESPs or IP addresses.

ISPs look at your sending history, volume, and frequency to assess your reputation. Sudden spikes in volume, inconsistent sending patterns, and sending to old, unengaged lists can all harm your reputation.

Email Authentication

Authentication protocols are technical standards that verify you are who you claim to be. They are a fundamental requirement to improve email deliverability and are no longer optional, especially with recent changes from Gmail and Yahoo.

• SPF (Sender Policy Framework): This record lists the IP addresses authorized to send emails on behalf of your domain. It prevents spammers from spoofing your domain from unauthorized servers.
• DKIM (DomainKeys Identified Mail): DKIM adds a digital signature to your emails. The recipient's server uses this signature to verify that the email hasn't been tampered with in transit.
• DMARC (Domain-based Message Authentication, Reporting, and Conformance): DMARC builds on SPF and DKIM. It tells receiving servers what to do with emails that fail authentication checks (quarantine them or reject them outright). A p=reject policy offers the strongest protection and is considered an email deliverability best practice.

Subscriber Engagement and List Quality

ISPs closely monitor how recipients interact with your emails. These engagement signals are a direct reflection of whether your audience values your content.

• Positive Signals: High open rates, click-through rates, replies, and marking your email as "not spam." These actions tell ISPs that your emails are wanted.
• Negative Signals: High bounce rates, spam complaints, unsubscribes, and deleting emails without opening them. These actions signal that your emails are unwanted and can quickly damage your reputation.

The quality of your email list is directly tied to engagement. A list built through opt-ins and regularly cleaned of inactive contacts will naturally have higher engagement and better deliverability.

How to Improve Email Deliverability: 12 Proven Strategies

Now that you understand the "why," let's dive into the "how." Here are 12 actionable strategies to improve your inbox placement.

1. Set Up and Verify Email Authentication (SPF, DKIM, DMARC)

This is the technical foundation of good deliverability. Without proper authentication, you're starting at a significant disadvantage.

• Implement SPF: Work with your IT team or ESP to create an SPF record in your DNS settings that includes all the services you use to send email (e.g., your ESP, your transactional email provider).
• Configure DKIM: Your ESP will provide a DKIM key that you need to add to your DNS records. This creates the digital signature for your emails.
• Deploy DMARC: Start with a p=none policy to monitor reports. Once you confirm that all legitimate emails are authenticating correctly, move to p=quarantine and finally to p=reject for maximum protection and deliverability benefit.

2. Warm Up Your IP and Sending Domain

You can't go from sending zero emails to 100,000 overnight. ISPs are suspicious of new senders with high volume. "Warming" is the process of gradually increasing your email volume over several weeks.

• Create a Schedule: Start by sending a few hundred emails per day to your most engaged subscribers.
• Increase Volume Slowly: Double your sending volume every 3-4 days as long as you maintain good engagement rates and low bounce/complaint rates.
• Monitor Your Reputation: Use tools like Google Postmaster Tools and Microsoft SNDS to monitor your IP and domain reputation during the warm-up process.

This process builds a positive sending history and proves to ISPs that you are a legitimate sender.

3. Practice Rigorous Email List Hygiene

Sending emails to invalid or unengaged addresses can quickly harm your deliverability. A clean list is an engaged list, so it's essential to practice rigorous list hygiene.

Start by using double opt-in. This involves sending a confirmation email that new subscribers must click to verify their address, which helps prevent typos and spam bots from being added to your list. You should also validate emails at the point of capture using a real-time validation service to catch errors or fake addresses immediately.

It's also important to regularly remove inactive subscribers. Implement a "sunset policy" to remove users who haven’t engaged with your emails in a specific timeframe, like 90-180 days. Before removing them completely, consider running a re-engagement campaign to try and win them back.

4. Never, Ever Buy an Email List

Purchasing email lists is a death sentence for your deliverability. These lists are often filled with:

• Spam Traps: Email addresses created by ISPs specifically to catch spammers. Hitting just one can get you blocklisted.
• Invalid Addresses: Which lead to high bounce rates.
• Uninterested Recipients: Who will mark your emails as spam, leading to high complaint rates.

Building your list organically through valuable content and clear opt-ins is the only sustainable way to ensure good deliverability.

Start by creating high-quality content like blog posts, guides, or free resources that your audience finds helpful. Use lead magnets such as eBooks, checklists, or exclusive discounts in exchange for email sign-ups. Make sure your opt-in forms are simple and visible on your website, landing pages, or social media. Hosting webinars or events is another great way to engage and grow your list. Always prioritize permission-based sign-ups to build trust with your audience.

5. Personalize Content and Segment Your Audience

Generic email blasts are dead. Subscribers expect content that is relevant to their interests and behaviors. Personalization and segmentation are key drivers of the engagement that ISPs want to see.

• Segment by Behavior: Group subscribers based on their purchase history, website activity, or past email engagement.
• Use Dynamic Content: Tailor parts of your email content based on subscriber data, such as their name, location, or interests.
• Send Triggered Emails: Set up automated emails based on user actions, like welcome series for new subscribers or abandoned cart reminders. These emails have exceptionally high engagement rates.

6. Optimize Your "From" Name, Subject Line, and Preheader

The first things a subscriber notices in their inbox are the "From" name, subject line, and preheader text. These elements play a key role in whether they decide to open the email or not.

The "From" name should be recognizable and consistent, such as your brand name or a combination of a person's name and the brand, like "Jane from ColdIQ." This helps build trust and familiarity.

The subject line needs to be clear, concise, and honest. Avoid using spammy trigger words like "FREE!", "URGENT," or ALL CAPS, as well as misleading claims, to ensure your email stands out for the right reasons.

Finally, the preheader text, which appears after the subject line, is an opportunity to add extra context and entice the recipient to click. Use it strategically to complement the subject line and grab attention.

7. Make It Easy to Unsubscribe

This might sound counterintuitive, but a prominent unsubscribe link is your friend. Hiding it will only lead to frustrated subscribers marking your email as spam, which is far more damaging to your reputation.

• One-Click Unsubscribe: Ensure your unsubscribe process is simple and immediate. Recent regulations from Gmail and Yahoo mandate a one-click unsubscribe header.
• Include a Link in the Footer: Place a clear unsubscribe link in the footer of every email.
• Consider a Preference Center: On your unsubscribe page, offer subscribers the option to "opt-down" (receive fewer emails) or choose the types of content they want to receive instead of opting out completely.

8. Monitor Your Sender Reputation and Blocklists

Proactively monitoring your reputation allows you to catch issues before they escalate.

• Google Postmaster Tools: A free and essential tool for any sender. It provides data on your domain reputation, IP reputation, spam rate, and authentication success for emails sent to Gmail users.
• Microsoft SNDS: Similar to Postmaster Tools, this provides reputation data for emails sent to Outlook/Hotmail users.
• Blocklist Checkers: Use tools like MxToolbox to periodically check if your IP or domain has been listed on any major email blocklists.

9. Maintain a Consistent Sending Schedule

ISPs and inbox providers favor predictable and steady sending patterns. Sending a relatively consistent volume of emails at a regular frequency – for example, daily or three times a week – helps establish you as a reliable, legitimate sender in their eyes.

You should actively avoid sending emails sporadically, such as sending a large batch once a month and then going silent. This kind of inconsistency can harm your sender reputation and make it harder for your emails to reach inboxes.

It's also crucial to prevent massive, sudden spikes in email volume, as this can be a red flag for spamming behavior. The main exception to this is a carefully planned and executed IP warm-up process, which gradually increases your email sending volume over time.

Ultimately, a stable and predictable sending schedule is a key component in building and maintaining a strong sender reputation over the long term.

10. Balance Your Image-to-Text Ratio

Emails that rely on a single large image can often resemble spam tactics and are a major red flag for spam filters. This approach can severely hurt your email deliverability rates and compromise the effectiveness of your message. To prevent this, it’s crucial to follow the 80/20 rule: ensure your email contains at least 80% text and no more than 20% images. This balance not only keeps spam filters at bay but also ensures that the core of your message is accessible to all recipients.

Additionally, always include descriptive ALT text for your images. ALT text serves as a backup to communicate the message of your images in case they don’t load properly—whether due to email client settings or slow internet connections. ALT text is also a significant step toward improving accessibility for visually impaired users who rely on screen readers to understand your content. For example, if your image contains a promotional banner, the ALT text should clearly describe the offer and direct the reader to where they can learn more.

Most importantly, any critical information or your main call-to-action (CTA) should always be presented in plain text, rather than being embedded within an image. For example, if you’re offering a discount or asking readers to click a link, ensure those details are explicitly written in text, so they remain visible and actionable even if images fail to load. By following these tips, you can create emails that are both visually appealing and highly effective in delivering your message.

11. Avoid URL Shorteners

Spammers often use URL shorteners, like those from bit.ly, to hide the actual destination of their malicious links. Because of this, many email spam filters are designed to treat shortened URLs with suspicion, which increases the likelihood that your message will be marked as spam.

To prevent your emails from being flagged, it's best to use full, descriptive links that point directly to your domain. This transparency not only helps your emails get past spam filters but also builds trust with your subscribers and their internet service providers (ISPs), as they can see exactly where the link leads.

12. Ask Subscribers to Add You to Their Address Book

This is a simple yet surprisingly powerful technique for improving email deliverability. When a subscriber manually adds your email address to their contacts or address book, it sends a strong positive signal to their inbox provider (like Gmail, Outlook, or Yahoo). This action essentially tells the provider that your emails are trusted and explicitly wanted by the recipient.

As a result, future messages from you are much more likely to land in the primary inbox rather than the spam folder. You can easily encourage this behavior by including a small, friendly note in your welcome email series or in the footer of all your emails, reminding them to add you to their contacts to ensure they never miss an important update or offer.

How to Fix Email Deliverability Issues

If you're suddenly experiencing a drop in open rates or an increase in complaints, you need to act fast.

Here’s a step-by-step guide on how to fix email deliverability:

1. Stop Sending: Pause all your email campaigns immediately to prevent further damage to your reputation.
2. Run a Technical Audit:
   
   • Check your authentication (SPF, DKIM, DMARC) using a tool like MxToolbox to ensure everything is passing.
   • Check your IP and domain against major blocklists. If you are listed, follow the delisting process for each blocklist.
3. Analyze Your Data:
   
   • Dig into your ESP reports. Which campaigns had the highest bounce and complaint rates?
   • Look at Google Postmaster Tools. Has your IP or domain reputation dropped?
4. Identify the Root Cause:
   
   • New List Source? Did you recently import a new list of contacts? This is a common culprit. Isolate and stop sending to this list.
   • New Content or Template? Did the problem start after a new email design or change in content? There might be an issue with your HTML, links, or image-to-text ratio.
   • Compromised Account? Is it possible your account was compromised and used to send spam? Change your passwords and enable two-factor authentication.
5. Clean Your List Aggressively: Run your entire email list through a reputable validation service to identify and remove invalid addresses, spam traps, and other risky contacts.
6. Begin a Re-Warming Process: Once you've fixed the issue and cleaned your list, don't just resume normal sending. Start a new, smaller-scale warm-up process by sending only to your most engaged subscribers for a week or two to rebuild your reputation.

Let ColdIQ Handle Your Deliverability Challenges

Struggling to keep up with the technical complexities of email deliverability? Your time is better spent closing deals, not worrying about SPF records and IP reputation.

ColdIQ's AI-powered platform and expert team manage the entire cold outreach process for you, from building a robust email infrastructure to ensuring pristine deliverability. We handle the domain warming, list hygiene, and technical setup so your messages land in the inbox, every time. We generate the qualified appointments; you focus on the conversation.

Book a free strategic call with ColdIQ today.

Frequently Asked Questions (FAQs)

What is a good email deliverability rate?

A good email deliverability (inbox placement) rate is 95% or higher. While the goal is 100%, it's realistic to expect a small percentage of emails to land in spam due to the varying algorithms of different inbox providers. Anything below 90% indicates a problem that needs immediate attention.

How do I check my email deliverability?

You can check your deliverability using a combination of tools like Google Postmaster Tools and Microsoft SNDS. They give you direct reputation and spam rate data from the two largest mailbox providers.

Why are my emails going to the Promotions tab in Gmail?

Gmail's algorithm automatically categorizes incoming mail. Emails that contain marketing language, promotional offers, and HTML-heavy designs are typically filtered into the Promotions tab. This is not the same as the spam folder. Landing in Promotions is expected for marketing emails and is not necessarily a bad thing, as users go there specifically to look for deals.

What's the difference between a hard bounce and a soft bounce?

A hard bounce is a permanent delivery failure, usually because the email address is invalid, doesn't exist, or has blocked you. You must remove hard-bounced addresses from your list immediately. A soft bounce is a temporary failure, often due to a full inbox, a server being down, or the email message being too large. ESPs will typically re-attempt to send to soft bounces a few times.

Does sending frequency affect deliverability?

Yes, sending frequency affects deliverability. Sending too frequently can lead to "email fatigue," causing subscribers to ignore your emails or mark them as spam. Sending too infrequently can cause subscribers to forget who you are, also leading to spam complaints. It's crucial to find a consistent frequency that provides value without overwhelming your audience. This is a key part of email deliverability best practices.

How to clean and segment an email list effectively?

Cleaning and segmenting an email list involves removing inactive subscribers, correcting invalid email addresses, and grouping your audience based on their preferences, behaviors, or demographics. Regularly cleaning your list helps maintain high deliverability rates and ensures you're reaching an engaged audience. Segmenting your list allows you to send tailored content, improving open rates and engagement. Use tools and metrics such as bounce rates, engagement history, and preferences to guide this process.

Best subject line practices to avoid spam filters?

To avoid spam filters, keep your subject lines concise and relevant, avoiding words or phrases commonly flagged as spam, such as "free," "limited time," or excessive punctuation. Personalization, such as including the recipient's name, can boost deliverability and engagement. Aim for a balance between creativity and clarity, ensuring the subject line aligns with the email's content to manage subscriber expectations.

When to use a dedicated IP versus shared IP for sending?

A dedicated IP is ideal if you're a large sender with consistent email volume, as it helps establish a solid sender reputation tied solely to your email activity. For smaller senders, a shared IP can be beneficial, as the reputation is distributed among users, provided it's well-maintained. The choice largely depends on your sending frequency, volume, and need for control over your sender reputation.

What is the 60 40 rule in email?

The 60 40 rule in email typically refers to the balance of content to visuals in your email design. It suggests that 60% of your email should consist of engaging content (text) while 40% can focus on visuals (images, graphics). This balance helps ensure your email performs well even if images fail to load and maintains a professional yet visually appealing appearance.

What is the 12 second rule for emails?

The 12 second rule emphasizes that recipients often spend an average of 12 seconds reading or skimming an email. To capture their attention effectively, keep your message clear and concise, use bold headings, and include a compelling call-to-action. Structuring your email for quick readability ensures your key points are conveyed within this brief window of engagement.