How can I improve my email reputation and deliverability?
Matthew Whittaker
Co-founder & CTO, Suped
Published 21 May 2025
Updated 16 Aug 2025
7 min read
Improving email reputation and deliverability is crucial for any sender, whether you are a marketer, a transactional email sender, or a large enterprise. It means your emails consistently reach the inbox, avoiding spam folders and blocks. A strong email reputation signals to mailbox providers that you are a legitimate and trustworthy sender, which is fundamental to successful email communication.
When your reputation is poor, your emails face higher chances of being rejected, delayed, or routed to the spam folder. This directly impacts your ability to engage with recipients, convert leads, and maintain effective communication channels. Understanding the factors that influence your sender reputation and implementing best practices is key to ensuring your messages land where they are intended.
Email authentication fundamentals
Email authentication protocols are the bedrock of good email deliverability. They help mailbox providers verify that an email truly originates from the claimed sender, reducing the likelihood of phishing and spoofing. Implementing these correctly is non-negotiable for improving your email reputation.
The primary authentication standards include SPF, DKIM, and DMARC. SPF (Sender Policy Framework) lets you specify which IP addresses are authorized to send mail on behalf of your domain. DKIM (DomainKeys Identified Mail) adds a digital signature to your emails, allowing recipients to verify that the email content has not been tampered with in transit. DMARC (Domain-based Message Authentication, Reporting, & Conformance) builds on SPF and DKIM, providing instructions to mailbox providers on how to handle emails that fail authentication, and offering valuable aggregate reports.
Beyond these, BIMI (Brand Indicators for Message Identification) allows you to display your brand logo next to your sender name in supported inboxes, further enhancing brand recognition and trust. Correctly configuring all these records in your DNS is a critical first step towards a healthier email reputation and improved deliverability.
This example DMARC record uses a 'p=none' policy, which means mailbox providers will not take action on emails failing DMARC, but you will receive reports. This is a safe way to start understanding your email authentication landscape. For more details on monitoring, consider exploring DMARC monitoring solutions.
Building and maintaining a healthy sender reputation
The quality of your email list profoundly impacts your sender reputation. Sending to unengaged or invalid addresses leads to higher bounce rates and spam complaints, which are strong negative signals to mailbox providers. Regularly cleaning your list by removing inactive subscribers and hard bounces is essential.
Implementing a double opt-in process is a best practice. This means subscribers must confirm their subscription, ensuring they genuinely want your emails and reducing the chance of spam trap hits. Also, provide a clear and easy unsubscribe option in every email. High unsubscribe rates are better than high spam complaint rates or being added to a blocklist (or blacklist).
Furthermore, consider segmenting your audience and tailoring content to their interests. This increases engagement, which is a significant positive signal for your reputation. A highly engaged list with low bounce and complaint rates will help you avoid being added to an email blocklist.
Healthy list practices
Double opt-in: Ensure all subscribers confirm their interest.
Regular cleaning: Remove inactive users and hard bounces promptly.
Segmentation: Target specific groups with relevant content.
Risky list practices
Single opt-in only: Increases risk of invalid addresses and spam traps.
Purchased lists: Often contain spam traps and uninterested recipients.
Ignoring bounces: Leads to poor domain reputation over time.
Engaging your audience and content quality
The content of your emails and how your recipients interact with them directly influences your email reputation. Mailbox providers analyze engagement metrics like open rates, click-through rates, and reply rates as positive signals. Conversely, high spam complaint rates and low engagement are detrimental.
To encourage engagement, focus on sending valuable, relevant content. Craft compelling subject lines that encourage opens without being misleading or spammy. Personalize your emails where appropriate and ensure your calls to action are clear. For example, understanding how to increase email click through rate can significantly boost your standing.
Avoid triggers that commonly land emails in the spam folder, such as excessive use of all caps, too many exclamation marks, or certain spammy phrases. Maintain a good text-to-image ratio and ensure all links are legitimate. Consistent sending volume is also important; sudden spikes can flag your account as suspicious, even if your content is good.
Monitoring and responding to deliverability issues
Even with best practices in place, issues can arise. Proactive monitoring is vital to catch and address deliverability problems quickly. Utilize tools like Google Postmaster Tools and other similar services provided by major mailbox providers. These tools offer insights into your domain and IP reputation, spam rates, and authentication errors, helping you identify and fix issues.
If you notice a drop in deliverability or emails landing in spam, investigate immediately. Check your bounce rates and complaint rates. A sudden increase often points to underlying issues like a compromised account, sending to outdated lists, or content triggering spam filters. You may need to take steps to improve email deliverability when emails go to spam. If you've been added to a blocklist (or blacklist), use a blocklist checker and follow the necessary delisting procedures. Recovering reputation takes time, but consistent good practices will yield positive results.
For new sending IPs or domains, a process known as IP warming is critical. This involves gradually increasing your sending volume over time to build a positive sending history with mailbox providers. Starting with high volumes from a new IP can instantly trigger spam filters. Remember that your IP and domain reputation are closely linked and both need attention.
Advanced strategies for long-term deliverability
To dive deeper into improving deliverability, consider the full scope of your email program. This includes the technical setup, such as ensuring your sending infrastructure is properly configured and that you are using a reputable email service provider. The choice of provider can significantly impact your baseline deliverability rates.
Beyond technical aspects, focus on the entire customer journey. Are your welcome emails optimized for engagement? Do you re-engage inactive subscribers, or do you remove them to protect your list quality? Consistent, high-quality engagement across all email types helps reinforce a positive sending reputation. This holistic approach ensures all elements of your email program contribute to strong deliverability and a robust email reputation, preventing your messages from being marked as spam or blocked outright.
Views from the trenches
Best practices
Always implement double opt-in for new subscribers to verify their consent and email validity, which significantly reduces spam complaints.
Regularly clean your email lists by removing hard bounces, soft bounces, and inactive subscribers to maintain high list hygiene and improve sender reputation.
Consistently monitor your email deliverability metrics, including open rates, click-through rates, bounce rates, and spam complaint rates, using tools like Postmaster Tools.
Segment your audience and personalize content to increase engagement, as high engagement metrics are strong positive signals for mailbox providers.
Gradually increase sending volume for new IPs or domains through a structured IP warming process to build a reliable sending history.
Common pitfalls
Sending to purchased or old email lists without prior verification, leading to high bounce rates and hitting spam traps.
Ignoring email authentication (SPF, DKIM, DMARC) or having misconfigured records, which causes emails to fail authentication and be marked as suspicious.
Sending inconsistent email volumes or sudden large spikes, which can trigger spam filters and damage your sender reputation.
Failing to provide a clear and easy unsubscribe option, leading frustrated recipients to mark your emails as spam.
Using spammy subject lines, excessive exclamation marks, or misleading content, which directly impacts user engagement and triggers spam filters.
Expert tips
Focus on the trend of your deliverability metrics, rather than day-to-day fluctuations, to understand the overall direction of your sender reputation.
Prioritize fixing issues that impact delivery before reputation, as a leading indicator of problems makes recovery easier.
Recognize that building a strong email reputation takes time and consistent effort, similar to a long-term training process.
Regularly audit your entire email program, from acquisition to content, to ensure all elements support optimal deliverability.
Engage in email communities and stay informed on industry changes to adapt your strategies for evolving mailbox provider requirements.
Expert view
Expert from Email Geeks says reputation is always about your prior performance.
2022-12-07 - Email Geeks
Expert view
Expert from Email Geeks says Google Postmaster Tools data is typically delayed by two days, unless sending volume is insufficient to meet minimum publication limits. However, positive trends indicate movement in the right direction.
2022-12-07 - Email Geeks
Summary
Improving your email reputation and deliverability is an ongoing process that demands attention to technical details, audience engagement, and consistent monitoring. By prioritizing strong authentication, maintaining a clean and engaged subscriber list, crafting relevant content, and actively monitoring performance, you can significantly enhance your chances of reaching the inbox. This proactive approach not only boosts your deliverability rates but also strengthens your brand's credibility and the effectiveness of your email campaigns.
