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Our Mission

Our number one goal is to help you become a better sender. We do this by assessing where you are today and giving you the resources to grow your email knowledge.

We’re committed to uncomplicating email.

Sender Score has been used by hundreds of thousands of marketers to assess their email sending reputations. Thousands of receivers and mailbox providers (MBPs) rely on Sender Score to make more accurate filtering decisions.

It all started back in 2005 when Return Path launched the Sender Score reputation metric: a first-of-its-kind measurement aimed at giving marketers real visibility into how their email messages were viewed by mailbox providers.

Powered by the Validity Data Network—the industry’s largest email data cooperative—Sender Score uses reputation-affecting complaints, traps, and deliverability data pulled directly from mailbox providers and message security agencies to generate your IP’s Sender Score.

Today, Validity has grown our suite of free assessments, tools, and resources powered by our technology to help email enthusiasts like you reach your next level of email success—whether you’re just starting out or you’re an experienced sender.

Frequently asked questions.

1. What does my Sender Score number mean?

All scores are based on a scale of zero to 100. Zero is the worst, and 100 is the best possible score. Your score represents an IP address measured against other IP addresses, much like a percentile ranking.

Sender Score is derived from a proprietary Validity algorithm and represents an IP address’s overall performance against metrics important to both internet service providers (ISPs) and their customers who receive your email. For senders, this score represents the overall health of your email programs as they appear to receiving systems. In most cases, scores are calculated on a rolling 30-day average.

2. How does Validity know so much about email sending behavior?

The Validity Data Network is a collection of more than 80 mailbox and message security providers around the globe that send and receive Sender Reputation Data to and from Validity.

This data network is the largest email data cooperative in the industry—collecting messaging data that affects billions of mailboxes around the world. Data is sourced from receiver networks globally to produce aggregated data services utilizing a wider and deeper view of sender reputation. Mailbox and Messaging Security Providers provide data and distribution as the foundation for Validity reputation and deliverability services. Validity reciprocates with processed data, scores, and services to help Mailbox Providers deliver legitimate mail and fight spam more efficiently and effectively.

Data from the Validity Data Network is used to power things like Validity Sender Certification and Sender Score. Validity uses this data to help senders manage their reputation by understanding performance with the mailbox and message security partners that can affect deliverability. Access to the Validity Data Network ensures that senders are receiving data and insights directly from the mailbox providers and message security agencies themselves. This allows us to provide you with information about reputation-affecting complaints, traps, and deliverability.

3. What are the indices of the Validity Sender Score algorithm?

Complaints: This score represents how complaints about that IP address compare to all other IP addresses observed by the Validity Data Network. Complaint rates are calculated as complaints divided by accepted mail. Your complaint score is a rank based on your complaint rate.

Volume: Sending volume is not inherently good or bad, but it’s an important part of the overall reputation algorithm. For example, an IP address that sends 100 messages and receives 99 complaints is problematic, while an IP address that sends 100,000 messages and receives 99 complaints is likely OK. A higher score equates to a larger volume monitored by the Validity Data Network.

External Reputation: This score shows how the IP address compares to all other IP addresses seen by the Validity Provider Network on a variety of external blocklists and allowlists.

Unknown Users: This score represents the rank of the IP address’s unknown user rate compared to all other IP addresses seen by the Validity Provider Network. Unknown user rates are taken directly from incoming SMTP logs of participating ISPs, and track how often an IP address attempts to send a message to an address which does not exist.

Rejected: This represents how often messages are rejected (meaning they bounced due to some policy reason, usually spam filtering or blocklisting) compared to other IP addresses seen by the Validity Provider Network.

4. Is the Sender Score an average of the other scores?

No. The Sender Score is derived using a proprietary formula developed by Validity based on modeling sending IPs versus their likelihood of engaging in behaviors viewed negatively by mailbox providers and filtering companies like Spamhaus. The various individual indices contribute to the overall Sender Score, as do additional data elements not represented by any individual index.

5. How is Sender Score data being used now?

Receivers use the Sender Score to inform their mail filtering decisions. A simple implementation may be to reject all mail with a Sender Score beneath some level they deem acceptable. A more complicated implementation may be to allow messages from IP addresses with Sender Scores above some threshold, but block senders who have recently hit a spam trap or generate very high complaint rates. Some ISPs use Sender Score to guide how many messages they accept from an individual IP address within a set period of time. This is often called “throttling” or “rate limiting.” For example, the higher the Sender Score, the more messages that IP address can send to that mailbox provider. With a lower Sender Score, attempts to send more messages than are allowed can mean your messages are rejected (usually as a temporary failure).

Universally, the higher your Sender Score, the better chance your mail will be accepted by a mailbox provider and delivered to your intended recipients. The lower an IP address’s or domain’s Sender Score, the more likely that ISPs and anti-spam systems, including those which do not query Sender Score directly, will reject or filter the mail.

Senders can use Sender Score data to monitor their own sending behavior and quickly identify problem spots. For example, identifying sources of complaints or knowing whether mail from your network hits spam traps can allow you to resolve any issues before they begin to impact delivery of all mail from your network.

6. Does getting removed from the Return Path Blocklist (RPBL) or improving my Sender Score guarantee my email will get delivered?

No. Sender Score does not directly block or accept email. Receiving email networks and ISPs may query Sender Score and use the result as a means of assessing their email traffic and allowing or rejecting email. Only the receiving network can ultimately determine if your email is delivered. Even if the receiving network does not utilize Sender Score data directly, they may be looking at similar metrics. Therefore, the work involved in improving your Sender Score generally improves the chances your email will be delivered everywhere.

7. What is Validity?

For over 20 years, tens of thousands of organizations throughout the world have relied on Validity solutions to target, contact, engage, and keep customers—using trustworthy data as a key advantage. The Validity flagship products – DemandTools, BriteVerify, Everest, GridBuddy Connect, and MailCharts—are all highly rated solutions for CRM data management, email address verification, inbox deliverability and avoiding the spam folder, and grid CRM applications. These solutions deliver smarter campaigns, more qualified leads, more productive sales, and ultimately, faster growth. For more information, visit and connect with us on LinkedIn, Instagram, and Twitter.