Sender Reputation: 5 Proven Tips to Improve It

Struggling to get emails noticed in crowded inboxes? The sender reputation might be to blame.

When it comes to email marketing, the sender reputation can make or break an email campaign’s success.

With over 361.6 billion emails sent and received worldwide in 2024, standing out in crowded inboxes is essential to maintaining a positive reputation.

In this article, we will discuss what sender reputation is, what affects it, how to check it, and reveal five actionable ways to improve it.

Keep reading!

What is Sender Reputation?

Sender reputation refers to a score assigned by an Internet Service Provider (ISP) to email senders, showing how trustworthy emails are.

To assess email sender reputation, ISPs take into consideration the following factors and metrics, such as:

• Contacts quality
• Email engagement level (open rate, click rate, unsubscribe rate, complaint rate, etc.)
• Email sending volume
• Email content quality
• Availability of email authentication

But there’s more to the story. To fully understand sender reputation, it’s important to explore its two key components – IP and Domain Reputation.

IP Reputation vs. Domain Reputation

IP reputation shows how trustworthy emails originating from a specific IP are based on the historical sending behavior associated with that specific IP.

You can choose either a shared or a dedicated IP address for email campaigns.

A shared IP means that multiple users send emails from the same IP address, which means that the sender reputation can be affected by other users’ actions. In contrast, a dedicated IP address is assigned to a single company or user, giving one complete control over its reputation, and is usually more expensive.

Now, let’s see what domain reputation is and how it affects the sender reputation.

Domain reputation refers to the trustworthiness of emails associated with a sending domain (a brand’s URL) – the part of an email address that comes after the “@” symbol.

Domain reputation is more complex to manage and fix than IP reputation due to several factors, such as email content, sending practices, and recipient engagement.

A good IP address alone isn’t enough if you have a poor domain reputation. High spam complaints or bounce rates can hurt a domain’s credibility and influence overall trust in emails.

Now that we’ve covered the differences between IP and domain reputation, it’s time to explore the factors directly affecting sender reputation.

What Affects Sender Reputation?

There are several factors impacting the sender reputation. Let’s explore them!

• Emailing frequency: Just as social media platforms might flag unusual activity, email providers do the same. Sending too many emails from a new IP can appear suspicious, potentially leading to blocklisting and impacting open rates, deliverability, and email sender reputation.

Best practice: Start with a few emails and gradually increase the number to establish trust with email service providers.

• Bounce rate: It shows how often emails fail to get delivered. Soft bounces are temporary issues (e.g., full inbox), while hard bounces (e.g., non-existent email addresses) are more serious and harder to resolve. A high bounce rate can lead to ISP blocklisting and harming email sender reputation.

Best practice: Clean email lists every three or six months and remove hard bounces.

• Falling into spam traps: Spam traps are inactive email addresses used to catch spammers. Engaging with these addresses violates anti-spam policies, such as CAN-SPAM Act and GDPR, leading to penalties (e.g., blacklisting) and damaging the sender reputation.

Best practice: Use double opt-in and verify email lists to avoid spam traps.

• Overall user engagement rate: This metric measures how recipients interact with emails. Metrics like open rates and click rates can reveal insights about subscriber engagement and interest in email content. Remember, unengaged addresses can hurt the sender reputation.

Best practice: Track engagement metrics and segment the email list to target active email subscribers.

Even though learning these factors is key to managing an email sender reputation, it’s also important to know how to check the sender reputation to identify and resolve any issues on time.

How to Check Sender Reputation

Determining email sender reputation can be challenging, as each email service provider uses its own criteria, but this fact should not prevent one from conducting regular checks.

In fact, understanding and managing an email sender reputation is a must to ensure emails reach your recipients’ inboxes rather than spam folders.

Tools like Sender Score can help check the email reputation. It provides a score from 0 to 100, calculated by analyzing data from the previous 30 days. The higher the score, the better the sender reputation is.

Here’s a simple overview of how to use Sender Score.

• Enter a domain or IP address and press “Let’s go.”

• Then, provide details like work email, annual email volume, and country.
• Next, tap “What’s my score” to see detailed information on DNS records, SSL certificates, and sender scores for each IP address. A reputation above 80 is considered to be good.

Now that you know how to check the email sender reputation, it’s time to explore some actionable ways to improve it.

5 Tips to Improve Sender Reputation

Realizing the sender reputation is poor can be disappointing, but focusing on its improvement is key.

We’ve put together some actionable tips to get it back on track.

1. Authenticate Emails

Email authentication is an important step in building trust with ISPs. It ensures that emails are verified as legitimate and not spoofed.

Key email authentication protocols to set up are SPF, DKIM, and DMARC.

SPF enables you to define which mail servers are authorized to send emails on behalf of the domain. This hinders spammers from using a specific domain to send unauthorized emails.

DKIM (DomainKeys Identified Mail) adds a digital signature to emails, which allows recipient email servers to verify that the email came from authorized servers and hasn’t been changed.

DMARC (Domain-based Message Authentication, Reporting, and Conformance) builds on SPF and DKIM to provide a policy that tells recipient email servers how to manage emails that fail authentication checks.

These authentication protocols protect a domain from being used for email spoofing and phishing attacks, leading to improved sender reputation.

2. Grow Email Lists Naturally

Building a quality email list takes time and effort, but the benefits are long-term.

The temptation may be high to purchase email lists, but this can lead to several problems:

• Purchased lists often include invalid or spam trap addresses, which can get a domain blacklisted.
• Sending emails to these lists can harm the email sender reputation, as recipients are less likely to engage with emails.
• These lists also violate data protection regulations like GDPR.

Instead, concentrate on organic email list growth strategies.

Offering newsletters is one of the most popular ways to grow email lists. Engaging pop-ups can encourage visitors to subscribe to the newsletter. Make the signup process easy and the value proposition clear.

Below is a great example of a clear and visually appealing pop-up.

Moreover, you can use social media to promote the email list and encourage followers to sign up. Offering incentives, such as discounts, in exchange for email addresses is a great way to attract new subscribers.

Last but not least, provide valuable content in the form of lead magnets, such as guides, ebooks, or webinars. Ask for peoples’ email addresses so they can access these resources.

Remember, a smaller but engaged list is more valuable than an extensive list of uninterested subscribers.

3. Take Care of Email Lists

Keeping an up-to-date email list is vital for a good sender reputation. However, over time, these lists can become cluttered with inactive or invalid email addresses, and even spam traps, which can all damage the sender reputation.

To avoid this, clean up email lists. One of the best ways to do this is by verifying emails. An email verification tool like mailfloss can help:

• Automatically clean lists in real-time, daily, monthly, or on a custom schedule
• Fix typos in email addresses
• Remove invalid or risky email addresses

To put this into practice:

Step 1:  Connect the email service provider with mailfloss
Step 2:  Set the preferences for email verification
Step 3:  Receive detailed reports

Prioritizing email hygiene pays off with stronger customer relationships, improved marketing performance, and sender score.

4. Work on Engagement

Engagement is a key factor in email sender reputation. ISPs carefully monitor how recipients interact with emails. To improve engagement:

Write Catchy Subject Lines:

According to recent research, 47% of email users open messages based on the subject line alone.

To make subject lines click-worthy, try these techniques:

• Spark curiosity: “You won’t believe what we’ve discovered…”
• Add FOMO (fear of missing out): “Last chance: Our biggest sale ends tonight!”

Improve CTAs to make people take the desired action by

• Using action words: “Get a Free Guide” instead of “Click Here”
• Creating a sense of urgency: “Buy Now – Limited Time Offer”

Craft engaging email content by

• Using short paragraphs and bullet points to make it easier for readers to grasp the information
• Personalizing content based on readers’ preferences/interests
• Including valuable information or offers in every email

After optimizing email engagement, the next step is to address and remove any email blacklists.

5. Get Rid Of Email Blacklists

Being on an email blacklist can damage an email sender reputation. To prevent blacklisting, it’s recommended to perform regular monitoring. Tools like MXToolbox can help in understanding if an address or domain is blacklisted.

If an address or domain is listed, follow these steps to fix the issue:

• For self-service blacklists: Find out their removal process. It usually involves submitting a request.
• For time-based lists: Improve email practices and wait until the automatic removal. These lists often remove IPs or domains if the emails’ performance has improved.
• For persistent issues: Reach out to the blacklist operator directly and work together to identify the root cause of the blacklist placement.

Prevention is always better than cure when it comes to email blacklists. We recommend following email best practices to avoid the headache of getting blacklisted and protect the email sender reputation.

Wrapping up

The sender reputation can make a huge difference in email marketing success. With our practical tips,  you can improve the sender score and the overall performance of email campaigns.

However, instead of trying all the tips at once, how about starting with email list cleaning? Try mailfloss for effective email verification and say goodbye to sender reputation issues.

FAQ about sender reputation

What is a sender reputation?

Sender reputation is the reputation inbox providers score senders on how trustworthy their email practices are. It affects whether emails end up in inboxes or spam folders.

How to check the sender reputation?

To check the email sender reputation, use tools like Sender Score, Google Postmaster Tools, or email monitoring services.

How do I fix my email sender reputation?

To improve the sender reputation, authenticate emails, grow email lists naturally, regularly clean those lists, and improve email engagement.