TL;DR: Email reputation determines whether your messages reach the inbox. It’s shaped by IP and domain reputation, engagement metrics, authentication, and content quality—making ongoing monitoring essential.
Introduction
As evolving technologies have advanced email marketing (closely followed by evolving strategies), one important factor has always been, and remains, a major player: your email reputation.
At its core, a brand’s email reputation is simply how internet service providers (ISPs) such as Google and Yahoo, email clients such as Outlook, and other receivers of mail, perceive the emails your company is sending. Multiple factors help determine this important benchmark, such as:
- Do your emails provide value for both new and old customers?
- Is your email constantly being flagged as spam?
- Is your email sending address ending up on any blacklists?
Marketers are fortunate today to have tools such as Return Path’s Sender Score to help measure and analyze their brand’s IP email reputation, and Cisco’s Talos as a domain reputation resource. The creators of these tools have broken down email reputation into two important subcategories, IP reputation and domain reputation. Each is very different from the other, but they are equally important in the grand scheme.
What is IP Reputation?
Of the two, IP reputation is more of a science. An IP reputation assessment looks at whether the email originating from your IP address (the string of numbers that is a unique identifier for the device you use to send email) contains any negative content that appears to be spam. The reputation factors in key metrics such as bounces, spam traps, complaints, and opens. Volume and frequency of the emails sent from the IP address also play a role in determining your IP’s reputation.
The first step in establishing an IP reputation is whether you want to use a shared or dedicated IP. A shared IP is one that’s used by several other companies or senders, and a dedicated IP is one that is owned and operated by one company or sender. Each provides a different approach in developing an IP reputation.
How to Improve IP Reputation
Improving your IP reputation requires consistent sending practices, strong list hygiene, and close monitoring of engagement signals. Since ISPs evaluate how recipients interact with your emails, your sending behavior plays a critical role in building trust.
Start by warming up your IP address if it’s new or hasn’t been used recently. Gradually increase your sending volume over time rather than sending large campaigns all at once. This helps establish a positive track record with ISPs.
Next, focus on maintaining a clean email list. Regularly remove inactive subscribers, invalid addresses, and hard bounces. Sending to outdated or purchased lists can trigger spam traps and significantly damage your reputation.
You should also monitor key performance metrics, including:
- Bounce rates
- Spam complaints
- Open and click-through rates
High complaint rates or low engagement signal to ISPs that your emails may not be wanted.
Consistency is another important factor. Avoid sudden spikes in email volume or irregular sending patterns, as these can raise red flags. Instead, establish a predictable cadence that your audience expects.
Finally, ensure your emails are relevant and valuable. Even with perfect technical setup, poor engagement will hurt your IP reputation over time.
What is Domain Reputation?
Domain reputation is a newer assessment technology. If IP reputation is a science, domain reputation is an art (tempered with scientific aspects). It factors in not only your IP address but also the domain attached to your email sending behavior. With the sending domain taking such a forward-facing role, your brand becomes a pivotal part of your sending reputation. If you switch IPs, the domain reputation will remain the same, good or bad, if sending from the same domain.
Two ways to help ISPs perceive your reputation as more trustworthy are to implement Sender Policy Framework (SPF), a simple open-source email validation system, and DomainKeys Identified Mail (DKIM) which lets an organization take responsibility for a message that is in transit. These both help establish identifiers for your sending domain.
How to Improve Domain Reputation
Domain reputation is closely tied to your brand identity, making it a long-term asset that requires both technical setup and strategic content execution.
The first step is to implement proper email authentication protocols, including:
- SPF (Sender Policy Framework)
- DKIM (DomainKeys Identified Mail)
- DMARC (Domain-based Message Authentication, Reporting & Conformance)
These protocols verify that your emails are legitimate and help prevent spoofing, which builds trust with ISPs.
Next, align your email practices with your brand by sending consistent, high-quality content. Since your domain is visible to recipients, engagement directly impacts how ISPs evaluate your credibility. Emails that are ignored, deleted, or marked as spam will weaken your domain reputation.
It’s also important to use a consistent sending domain. Frequently switching domains or using multiple domains without clear structure can dilute your reputation and create confusion for ISPs.
Pay attention to link trustworthiness as well. All links in your emails—including those in footers and preheaders—should point to secure, reputable domains that align with your brand. Suspicious or mismatched links can harm your credibility.
Lastly, keep your privacy policy and unsubscribe process transparent and easy to access. These elements signal legitimacy and improve user trust, which indirectly supports stronger engagement and better domain reputation.
A few more factors that affect your email sending reputation
In addition to IP reputation and domain reputation, Email marketers must also consider qualitative measures that can affect deliverability, such as:
- Content of your company’s privacy policy
- Trustworthiness of any links in your email message, including preheaders and footers
- Overall value of the content provided in your email message
Maintaining your email reputation requires a strategic blend of art and science, but the end goal is always the same – to get your email into the inbox. Both IP and domain reputation are major players in achieving this, and both must be taken into account when assessing deliverability.
Good business practice is to constantly monitor and uphold the standards of both your IP and domain reputations.
Want help? The experts in Act-On’s Email Reputation Management and Deliverability Service can provide hands-on support to help you boost your email delivery reputation.