Email Sender Reputation | Everything You Need To Know About

If your email sender reputation is low, chances are your email campaign sucks!

Now, I could tell it without checking for any numbers from your email campaign. 


Simple. A lower sender reputation = lower email deliverability and a lower deliverability means you are already losing out money spent on per email cost per delivery. 

In this, article, I have tried to solve this problem with an email sender reputation 101 guide.

In this article we will discuss what email sender reputation is, explore the various factors that affect it, guide you on how to check your email reputation, and provide actionable tips on how to improve your sender reputation. 

Lastly, we’ll address some frequently asked questions on the topic as a part of revision.

So, first things first.

What is “Email Sender Reputation” ?

Email sender reputation, often referred to as your ‘email reputation,’ is a crucial factor that influences your email deliverability. It’s a score assigned by Internet Service Providers (ISPs) based on the quality of your email sending practices. This score determines whether your emails land in the recipient’s inbox or spam folder.

Email sender reputation process visualized

Now, email sender reputation has two important concepts associated with it, viz., Domain Reputation and IP Reputation

Domain Reputation is tied to your domain name and is influenced by factors such as the age of your domain, your sending history, and the quality of content you send. Also, if you have a poor IP reputation, your domain reputation will suffer. A well-established domain with a history of sending high-quality content will have a good domain reputation, so it will have  a naturally better email sender reputation.

IP Reputation, on the other hand, is linked to the IP address from which you send emails. Most email service providers (ESPs) offer a pool of IP addresses they use to send emails on behalf of their clients. These IPs are typically shared between many email accounts, making them a cost-effective option for most senders. So, your sender reputation is directly linked to the overall health of the IP pool. If you send emails from an IP address that has been used for spamming or sending low-quality content in the past, your IP reputation may be negatively affected which can lower your email sender reputation

Why is email sender reputation important for email outreach?

Here are 3 reasons why you should always try to maintain a good sender reputation for email outreach:

1. Deliverability and Trust

Sender reputation determines if your emails reach inboxes or get filtered as spam. High sender reputation builds trust with ISPs and recipients mail boxes, leading to better email engagement. Low reputation reduces email deliverability and hinders communication.

2. Avoiding the Spam Label

A bad reputation increases the risk of emails being labeled spam, leading to recipient avoidance.Good reputation ensures content aligns with recipient expectations and avoids spam filters.

3. ROI and Conversion Rates

If you have a high sender reputation, chances are you will get maximum email deliverability that translates to higher open rates, clicks-through rates , and ultimately, conversions.

4. Inbox placement

Your email sender reputation dictates where your email lands. A higher email sender reputation can help your emails land in the recipient’s inbox, while the low sender reputation often divert it to SPAM.

5. Cost effectiveness

A strong sender reputation saves you money by maximizing email delivery and reducing wasted sends. So, you save cost per email sent.

What are some factors that affect email sender reputation? 

Here are some important factors that affect your email sender reputation:

1. User engagement

User engagement metrics determine your sender reputation. For example,

  • Open Rates: High email open rates signal relevant content and engaged recipients.
  • Click-Through Rates (CTR): A strong CTR indicates compelling content and user interest.
  • Reply Rates: Encouraging replies contributes positively to your reputation.
  • Starred Emails: When recipients star your emails, it reflects favorably on your sender reputation.

Related: Email Open Rate: Is It the Most Important Email Marketing Metric?

2. Spam complaints

Everytime recipients hits “Mark as Spam” on your emails, it affects your sender reputation and credibility. High spam complaint rates hamper your email deliverability to a great extent.

3.  Sending volume and frequency

Sudden spikes in email sending volume or erratic sending patterns can raise red flags for spam filters. Also, sending large volume of emails too frequently may lead to fatigue and increased number of spam reports.

4. Bounce rates

When your emails don’t land in the recipient’s inbox, it’s referred to as “email bounce”. They can be of two types Soft bounce (temporary delivery failure) and Hard bounce (permanent delivery failures). Both of them can damage your sender reputation due to their negative impact on email deliverability.

Read more: How to Reduce Email Bounce Rate for Cold Email Outreach?

5. Unsubscription

While some unsubscribes are natural in your email campaign, excessively high unsubscribe rates signal a content disconnect or sending fatigue to ISPs, potentially harming your sender reputation.

6. Spam traps 

ISPs use cleverly disguised email addresses (spam traps) to catch senders with bad hygiene (bought lists, unclean lists). Landing in a trap tanks your sender reputation, making future emails less likely to reach inboxes.

factors that affect email sender reputation

7. Email authentication 

Implementing email authentication protocols like SPF, DKIM, and DMARC verifies you as a legitimate sender, improving sender score and keeping your brand out of spam.

8. Shared IP

Free email Service providers such as Gmail, Outlook, Yahoo offers a set of IPs to its users to send emails from. These shared IPs inherit the reputation (good or bad) of all users on that IP pool and it can impact your deliverability. 

Overall, your past email engagement speaks of your future deliverability. A nurtured list of engaged subscribers who consistently open and interact with your content acts as a golden ticket to a stellar sender reputation. ESPs take notice of this positive engagement and reward you with inbox placement.

On the flip side, if your email history is riddled with complaints and bounces from sending to an unverified list (like one you might have gotten from a suspicious guy on Reddit!), your sender reputation takes a nosedive. ISPs interpret these red flags as a sign of spammy practices and make it increasingly difficult for your future emails to reach inboxes.

How to check your email reputation? (4 Methods)

Here are some ways you can check your email reputation. 

#1. Use third-party tools 

This the the most accurat way to measure your email sender reputation.These mailbox-specifc tools use various factors, including sending practices and user engagement, to sort your emails. Also, these tools can analyze these factors to assess your organization’s sending reputation, helping identify potential delivery issues.

Example: Sender score, Spam Haus Microsoft SDNs

However, these tools alone may not capture the full picture on your sender repuation, so I recommend you use these tools along with the other options given in this list.

#2 Send an email to yourself

This is a simple yet effective way to check if your email is being marked as spam. By sending an email to yourself, or to a separate email account you own, you can see firsthand whether your email lands in the inbox or the spam folder. If your email ends up in the spam folder, it’s a clear indication that you need to work on your sender reputation

#3 Monitor your email campaign analytics

Your cold email analytics can provide a wealth of information about your email sender reputation. An increasing trend of high bounce rates, low open rates, and low click-through rates can all be indicators of a poor sender reputation. So, monitor delivery and open rates over time to gauge sending reputation.  Since mailbox providers differ, track these metrics by domain for a more granular view of potential issues.

Read more: Cold Email Analytics: 15 Sales Email Metrics & KPIs to Track

#4 Check for IP and domain denylisting

You should also check for IP and domain denylisting. Denylists are lists of IP addresses or domains that have been reported or observed sending spam emails. If your IP or domain is on a denylist, your emails are likely to be blocked or sent to the spam folder. Tools like MXToolbox provide denylist checks.

Regular monitoring and taking quick action when issues are identified are the keys to a robust email sender reputation.

How to improve your email sender reputation?

If you feel you have not achieved a sufficient email sender reputation yet, here are some practical strategies to boost your email sender reputation:

#1 Check Email Reputation Regularly

Consistently keep an eye on your email reputation and track them over months and quarters. Various third-party tools can help you monitor your sending reputation. These tools use diverse data sources to calculate your sender score, providing a snapshot of your IP and domain reputation. Also, proactively monitor blacklist  to identify and address potential reputation issues before they land your emails in spam folders.

#2 Buy Look-alike Domains

Domains that resemble to yours are known as “look-alike domains”. They are often misused for sending spam and phishing emails. By securing these domains, you can prevent potential impersonators from tarnishing your domain and reputation. This method is not a direct booster for sender reputation, but it helps in the long-run.

#3 Adopt Email Authentication Measures

Email authentication protocols such as SPF, DKIM, and DMARC can safeguard your domain from email spoofing. While implementing these protocols involves technical know-how, it’s a necessary step to secure your email sender reputation and improving email deliverability.

Read more: How to authenticate SPF, DKIM and DMARC for Microsoft 365?

#4 Improve Your Email Engagement Metrics

A/B test  your various email components such as subject lines, Body copy, value-proposition, email-sending schedule etc., to improve your overall email engagement. Improving metrics such as open rates, CTRs, subscription rate etc. will naturally boost your email sender reputation. 

Craft your emails in a way that piques interest and prompts recipients to open them. The content of the email is equally important. Design it well, keep it concise, and make ‘call to actions’ work for you.

We have covered more tips on improving cold email engagement in our free Cold Email Masterclass.  Make sure you check it out.

#5 Keep Your Email List Clean

High bounce rates negatively impacts your sender reputation. One of the main reasons for high email bounce rates are invalid emails that don’t exist anymore in the system. So, always verify your emails before putting them on campaign. 

Check out my article “How to Check If An Email Is Valid or Not (7 Ways)” for more information on email validation using free and paid resources. 

Alternatively, you can use use email verification tools to automate the process for bulk email lists (but they are paid).

Read more: Best Email Verification Tools To Clean Prospect List in 2024

Note: Also, keep your mailing list clean by removing inactive subscribers and regularly updating your list.

#6 Stay Clear of Spam Traps and Complaints

As already mentioned, spam traps and spam complaints can severely damage your sender reputation. Avoid sending emails to users who have not opted in to your mailing list. In fact, try to include a double opt-in procedure for your campaign emails. 

It’s also important to avoid buying email lists from the unknown and shady sources if you are just starting out your cold email game. Instead, building your email lists organically by prospecting from different sources can help you stay clear of spam traps. 

Also, make it easy for your email recipients to unsubscribe from your emails to reduce the number of spam complaints.

#7 Leverage Feedback Loop (FBL)

The FBL tool provided by most mailbox providers and ESPs tracks spam complaints and engagement. If your spam complaints skyrocket, you can be assured that your email sender reputation will also be affected.

#8 Use BIMI 

Brand Indicators for Message Identification (BIMI) ienables the display of brand-specific logos on authenticated emails. It serves as a visual marker, enhancing recipient trust and engagement in your emails. 

BIMI for email to improve email sender reputation

It combines brand marketing with email security, giving your receipients a safer and more personalized inbox experiences. By verifying the sender’s identity, BIMI improves email deliverability and sender reputation.

#9 Adhere to Can-SPAM Compliance

While the CAN-SPAM Act itself doesn’t directly guarantee deliverability, following its guidelines build trust with recipients and mailbox providers. By adhering to CAN-SPAM’s requirements for clear identification, unsubscribe options, and avoiding deceptive practices, you reduce the chances of complaints that can negatively impact your sender reputation. This, in turn, improves email deliverability as mailbox providers are more likely to see you as a legitimate sender.

#10 Consistent Email Frequency

Consistent email frequency is key to sender reputation. Bombarding inboxes can trigger spam filters, while radio silence makes recipients forget who you are. Finding a sending cadence in your email frequency keeps engagement high and maintains a positive sender reputation.

To conclude, improving email sender reputation is not a overnight things, it slowly build up over time. By following these practical tips, you can ensure your emails land in your receipients’ inboxes, catch tration and lead to successful email outreach campaigns.

Improve your email sender reputaion using

If you have been running cold email outreach for a while and seeing a lower engagement rate on your emails,  you can try is a powerful AI-enabled Sales Engagement Platform designed to improve your email sender reputation and ensure your emails reach the inbox of your target audience. Here’s how:

Spam Test: conducts a thorough examination of your email accounts and campaign configuration to identify and rectify any potential issues prior to launching a campaign. This includes verifying authentications such as SPF, DKIM, and DMARC records on your email account and offering solutions to rectify any detected problems. 

Free Spam test report produced by for improving email sender reputation

Additionally, it scrutinizes your email formatting for potential issues such as missing alt attributes in images, harmful HTML or JavaScript elements, and short URLs in your email.

It also meticulously examines all the links embedded in your email campaign, alerting you if these links are either broken or have previously been flagged as phishing attempts. This ensures the integrity and effectiveness of your email campaign.

✅ Automated Domain Warmup: offers FREE automated domain warmup tool called “Warmup Hero”. It helps you gradually increases the volume of your outbound emails, helping to establish a positive sending reputation with Email Service Providers (Gmail, Outlook & more) over time.

scale up your email sending using

Free Unlimited Email Validation: automatically checks for the email validation of your email list before starting a campaign. Also, it identifies and removes hard bounces from your email list. This prevents you from repeatedly sending emails to invalid addresses, which can harm your sender reputation. 

free email validation using

SPF, DKIM, and DMARC Authentication: supports these email authentication protocalls, which verify that your emails are from a trusted source. This can significantly improve your sender reputation and email deliverability. 

✅Inbox Rotation:’s Inbox Rotation feature allows you to send emails from multiple inboxes in a rotating manner, which can significantly improve your email deliverability and sender reputation. By distributing your emails across multiple inboxes, you reduce the risk of any single inbox being flagged as spam.

Email Personalization: allows you to personalize your cold emails using features like A/B testing, Spintax, custom merge tags  making them more engaging and personalized and less likely to be marked as spam. 

Detailed Reporting: provides detailed reporting and analytics on your email campaigns, including open rates, click-through rates, and bounce rates. By monitoring these metrics, you can identify potential issues and make necessary adjustments to improve your sender reputation. 

free detailed reporting using

By leveraging these features, can help you maintain a strong email sender reputation, ensuring your cold email campaigns are as effective as possible. 

Still unsure if works or not for your business?

Try this 14 Days Free trial to see if it fits your needs. (No credit card required)

Email sender reputation – F.A.Q

Q. How to check email sender reputation?

Here are some ways to check email sender reputation.

1. Use Online Tools: Use online platforms like ‘’, `Gmail Postmaster`, and `Microsoft SNDS` to get a numerical representation of your sender reputation.
2. Conduct Email Tests: Send test emails to yourself or use services like `` to evaluate your email’s deliverability and reputation.
3. Review Deny Lists: Check if your IP address or domain is on any deny lists, which could negatively impact your reputation.
4. Examine Email Metrics: Analyze your email metrics such as sending history, bounce rates, complaint rates, and engagement rates for insights into your reputation.

Q. What is email sender reputation?

Email sender reputation is a score that Internet Service Providers (ISPs) assign to an email sender based on their email sending behavior. It’s influenced by factors such as spam complaints, bounce rates, and email engagement. This score impacts whether your emails land in the recipient’s inbox or spam folder. It’s a combination of your IP reputation and domain reputation, both of which contribute to your overall email deliverability.

Q. How to improve sender score?

Improving email sender reputation involves several key steps. First, ensure your email lists are clean and up-to-date to avoid bounces. Second, maintain a consistent sending volume to avoid being flagged as spam. Third, engage with your recipients in a meaningful way to encourage them to open and interact with your emails. Lastly, monitor your sender score regularly and take corrective actions when necessary. These practices will enhance your sender reputation and improve email deliverability.

Q. What is a good sender score?

A good sender score typically ranges between 80 and 100. Data from Return Path states that 20% of emails from senders with scores below 70 get blocked or go to the spam folder. A score above 90 indicates excellent sender reputation, with 92% of emails reaching the inbox

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