Sender Score

Sender Score is a metric (0–100) that reflects the reputation of an email sending IP address, maintained by Return Path (now part of Validity). Mailbox providers like Gmail, Outlook, and Yahoo use IP reputation — alongside other signals — to determine whether to deliver your emails to the inbox, the spam folder, or block them entirely. A Sender Score above 80 is generally considered healthy; scores below 70 often correlate with deliverability problems.

What Affects Your Sender Score

Your Sender Score is influenced by: the volume and consistency of your sending (sudden large spikes look suspicious), the percentage of your emails that bounce (invalid addresses indicate poor list quality), the spam complaint rate (recipients marking your emails as spam directly damages your reputation), the engagement rate of your sends (high engagement signals that recipients want your emails), and the history of your IP (newly warmed IPs start with lower scores and build reputation over time).

How to Improve Your Sender Score

The most effective ways to build and maintain a good Sender Score are: sending only to engaged subscribers, regularly removing inactive addresses (those who haven’t opened in 6+ months), using double opt-in to ensure list quality, authenticating your sending domain with SPF, DKIM, and DMARC, and gradually increasing sending volume from new IPs (“warming” them) rather than sending at full volume immediately. Monitoring your Sender Score monthly helps you catch problems before they become deliverability crises.

Shared vs. Dedicated IPs

Most small and mid-size businesses send email from shared IP addresses — meaning your Sender Score is partially determined by the behavior of other businesses using the same IP. This is generally fine for moderate sending volumes. High-volume senders (100,000+ emails per month) should consider dedicated IPs, which give you full control over your sending reputation but require more proactive management.