Domain reputation is a score assigned to your domain based on factors like email engagement, spam complaints, and bounce rates. A poor reputation can lead to emails being rejected or landing in spam folders.

To maintain a good domain reputation, it's essential to follow email best practices such as sending relevant content, avoiding spammy language, and maintaining a clean mailing list.

One of the best tools to monitor domain reputation is Google's Postmaster Tools. It provides insights into your domain's performance, including spam rates, authentication status, and reputation scores.Google Postmaster Tools