Sender reputation is a score by ISPs indicating email trustworthiness, influenced by contact quality, engagement, volume, and content.
IP vs. Domain Reputation: IP reputation is based on a specific IP's history, while domain reputation involves the sending domain's credibility.
Factors affecting sender reputation include emailing frequency, bounce rate, spam traps, and user engagement rate.
Check sender reputation using tools like Sender Score, which analyzes data to provide a score reflecting email trustworthiness.
Improve sender reputation by authenticating emails, growing lists naturally, maintaining list hygiene, and enhancing engagement.