Every email that you send travels through an IP address, and every IP address has a reputation attached to it.

The IP reputation is used to tell if the IP address has been used to send spam and unwanted bulk emails (UBE).

ISPs and recipient servers will use the IP to determine how your incoming emails will be handled (delivered to the inbox, delivered to the spam folder, rejected completely, etc).

The ISPs and recipient servers will also check your sending domain reputation (which includes your sending history, how many spam traps have you hit, how many spam complaints you have received, if your SPF & DKIM have been set, and so on). Your sending domain reputation combined with the IP reputation is known as your sending reputation.

Your IP reputation can change over time and you can help it stay positive by following the steps outlined in our best practices guides.