Email Sender Reputation

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by Nataliia Polomkina Outreach Specialist at Mailtrap Email Delivery Platform

Table of Contents

Definition of email sender reputation

Email sender reputation is a score that Internet Service Providers (ISPs) assign to an organization based on the quality of their email content, the quality of their contacts, and the engagement levels of their previous emails. A good sender reputation score is essential for successful email campaigns, as it helps ensure that your emails are delivered to recipients’ inboxes and not diverted to spam folders. A low sender reputation score can significantly reduce your deliverability rate and harm your email marketing efforts. An email sender’s reputation consists of IP and domain reputation.

What is IP and domain reputation? 

Domain reputation is the opinion recipients have of a given domain, like an email address or a Return-Path Domain, which helps them determine if the emails should be sent to the inbox or be blocked. 

This reputation is taken into account when the domain is being used anywhere, like the address being sent from, the Return-Path Domain, the DKIM Signing Domain, as well as all the links, headers, content, and brand assets included in the message. 

We can consider domain reputation as if it was a personal reputation one has with each receiver, depending on experiences, or with whom one is connected. 

Every receiver will observe how the domain is employed in a message and how it is accepted in the recipient’s inbox, then use its particular scoring system to allocate a reputation based on the collected data.

It is essential to understand the importance of domain reputation in terms of email deliverability. If any shady or spammy content is sent, or the content gets a low response rate, the domain will have a poor reputation. This will impact deliverability which can result in a decrease in open rates, customers complaining that messages are not arriving, and valuable messages going to the spam folder.

Switching domains might appear to be a simple option, but this will cause suspicion in the same way as a ‘bad’ domain. For this reason, it is beneficial to maintain a good domain reputation as an ongoing project. 

There are also some practices that can help to improve it, such as targeting engaged recipients, deleting unengaged people, reviewing security measures of online forms, and ensuring content are relevant and actionable to increase inbox placement and engagement.

Internet Protocol (IP) reputation is the amount of trust that inbox suppliers place in a particular IP address when the email is sent. 

IP addresses are a combination of numbers like that are used to identify devices connected to the Internet. When an email is sent, inbox providers look at elements such as the age of the IP, the location of the IP, the sending history, the presence of the IP on any block lists, and the reverse DNS lookup (PTR Record) to assess the reliability of the IP and decide if the email should be delivered to the inbox or marked as spam. 

For instance, a record of low bounce rates and minimal spam complaints for emails sent from an IP will increase its trustworthiness, whilst a lot of complaints will damage its reliability. 

Your IP is like your email service provider’s address, and your IP reputation is the level of trust inbox providers have in that address. Moreover, keep in mind that an IP address has many reputations, one for each recipient it interacts with.

The type of IP setup you choose for sending emails is essential, and you have two primary options: utilizing your own, devoted IP or sharing an IP with other senders. 

The central distinction between a committed and shared IP address lies in who is using that IP to send an email: 

  • A dedicated IP address is an IP address designated to send messages only from you, so the notoriety is based solely on your activities. 
  • A shared IP address is an IP address shared among you and other senders (generally, you’ll be pooled with comparable estimated senders and organizations). The standing is then worked on the activity of all senders that are utilizing a similar sending IP. 

Dedicated IPs must be warmed up gradually because they begin with no notoriety, require a consistent effort to be kept up, and are less sympathetic to blunders: even a minor error (for example, emailing too numerous invalid addresses) can promptly influence notoriety. 

IP notoriety is firmly attached to deliverability: suppliers need to secure clients from spammy and malicious movement and use IPs to decide the nature of a sending condition and make suspicions about the messages that are sent from it.

Related: Outbound email and processes podcast with Bill Stathopoulos

Factors that affect an email sender reputation

Sender reputation refers to the reputation of your email-sending IP address that signals to email inbox providers whether you’re a trusted sender. 

Eight factors that influence IP reputation and email deliverability are: 

1. How many messages has your server sent?

The number of email messages sent from your server is a key factor in determining your sender’s reputation. Sending too many emails can be seen as spammy activity and can lead to your IP reputation being adversely affected. It is important to regulate the number of emails sent to ensure that your reputation remains in good standing.

2. How many of your messages have been flagged as spam?

Email messages that are flagged as spam can harm your sender’s reputation. It is essential to use an email authentication system to ensure that your messages are not marked as spam. It is also significant to use an email service provider that offers feedback loop services so that you can be notified when one of your messages is marked as spam.

3. How many of your messages have bounced?

Bounced messages indicate that your messages are not reaching the intended recipients. This can be caused by an invalid email address, an inactive email address, or a full inbox. Bounces can also be caused by a blocked IP address or domain. It is indispensable to regularly clean your email list and remove any inactive or invalid email addresses.

4. How many of your messages have been opened or clicked?

User engagement is one of the most influential factors that determine your sender’s reputation. If your messages are not being opened or clicked, it can signal to email inbox providers that your content is not relevant to your recipients. It is critical to regularly monitor user engagement and use A/B testing to optimize your messages for maximum engagement.

5. Quality of list hygiene and maintenance

A clean email list is essential for maintaining a good sender reputation. It is essential to regularly remove any inactive or invalid email addresses from your list, as well as any addresses that have been marked as spam. You should also ensure that all of your email addresses are opt-in and are collected using double opt-in methods.

6. Content of email messages 

The content of your email messages should be relevant and engaging to your recipients. Emails that contain irrelevant content or are overly promotional can be flagged as spam, which can hurt your sender’s reputation. Additionally, it is significant to ensure that your emails are properly formatted and do not contain any spammy language or triggering words.

7. Formatting of email messages 

The formatting of your email messages can also impact your sender’s reputation. Emails that are formatted poorly can be flagged as spam.

8. User engagement 

You should consider using personalized content that is tailored to your recipients. This can help improve user engagement and make your emails more relevant.

Low sender reputation scores can be caused by factors such as high bounce rates, poor list hygiene and maintenance, high spam complaint rates, and poor content and formatting of email messages.

How to check your sender reputation

It would be best to use specialized software to check sender reputation indicators. You will need to enter your IP address or domain name and run the check. The software will provide you with a score or rating for your sender’s reputation, as well as detailed information about any potential issues or factors that may be affecting it.

Here are a few options:

  • Sender Score, provided by Return Path, allows you to check the reputation of your sending IP address or domain. You can enter your credentials and receive a score out of 100, as well as detailed information about your sending reputation.
  • MX Toolbox allows you to check the reputation of your sending IP address or domain and perform various other analyzes to identify potential issues with your email infrastructure.
  • GlockApps provides various tools for testing and monitoring email deliverability, including a sender reputation checker.
  • Postmark email delivery service provides a sender reputation checker that allows you to identify the reputation score of your IP address or domain.

Each tool uses a different methodology and has a different set of data. Nevertheless, it’s worth running a few of them to see where you stand now. You can also check your sender’s reputation by monitoring the deliverability and response rates of your emails.

How to maintain a good sender reputation

As we said above, ISPs often use various metrics to evaluate the reputation of email senders. Meanwhile, there are standard practices to maintain a good reputation with all the ISPs:

  1. Obtain explicit permission from recipients before sending emails. Make sure you are sending emails to people who are interested in receiving them. That helps to reduce the number of spam complaints and unsubscribes.
  2. Use a double opt-in process. Requiring recipients to confirm their subscription helps to reduce the number of invalid email addresses on your list and improve its overall quality.
  3. Provide an easy way to unsubscribe. It’s an essential rule of any email marketing campaign, not only in terms of the best performance but in terms of the law. Ensure recipients can quickly opt out of receiving emails by including an unsubscribe link in every message you send.
  4. Use a reputable email service provider. Choose an ESP that has a good reputation and follows best practices for email delivery.
  5. Monitor your sending metrics. Use tools for email deliverability and reputation monitoring to track your sending metrics and identify any issues that may be affecting your reputation.
  6. Keep your email list clean by removing inactive or invalid email addresses.
  7. Use a consistent “From” name and address to build trust with your recipients and improve your reputation.
  8. Provide recipients with qualitative email content. Use clean, concise subject lines and avoid using spammy tactics like excessive use of capital letters, exclamation points, or clickbait headlines.
  9. Implement authentication technologies like SPF and DMARC and generate DKIM record
  10. To help protect your domain and improve your reputation.

Remember that sender reputation isn’t something you can build overnight. It takes years for the best IPs to raise a reliable and trustworthy reputation, yet it still can be ruined with one failed mass-sending campaign. Follow best practices to gain respect for your domain and IP address, and test what works for your audience over and over again.

Suggested mentors to help you make sense of Email Sender Reputation

Nicolas Moulin

Email Marketing for Fashion Brands - Partner @ Seven to One

If you are looking to grow your ecommerce through performance marketing, email marketing, or simply by brainstorming some ideas, I’d be super excited to talk!

Mark Cann

Mark Cann B2B outbound and demand gen specialist

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Vassilena Valchanova

Digital Strategist & Trainer - Passionate about Content Marketing and CRO

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Dani Hart

Senior Account Director @ NEWPORT ONE

Feeling burned out? After years of working with CEOs, Heads of Growth, & Marketers from all over the world, I have stories & experience ready to support you on your growth journey. I’ll help you identify your biggest opportunities for sustainable growth for yourself and/or your business.

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