Depending on your package level you either have a dedicated sending IP address or you are using a shared sending IP address. All Silver+ customers are given dedicated sending IPs while Free, Lite, and Bronze customers all share sending IP addresses.

In order to determine your sending IP(s) at the Silver or higher level, please login to your primary account and visit this page:

http://sendgrid.com/whitelabel/wizard/page/2

Your IP(s) are displayed at the bottom of the page and are associated with the A records.

If you are on a shared IP address please contact the SendGrid Support team via chat, email, or phone for more information about your sending IP address.

For all account levels, you can also send a message through your account to have the sending IP address displayed in the headers of your message. For example here is such a header found in Gmail:

Received: from o1.email.sendgrid.com (o1.email.sendgrid.com. [74.63.202.100])