The Twilio SendGrid Marketing Campaigns Contacts API allows you to add, update, and delete contacts in your SendGrid account. You can also import and export contacts in bulk via CSV.
For more guidance on working with contacts, see Create and Manage Contacts.
Building and maintaining a healthy contact list is an essential first step in building trust as an email sender. A healthy contact list also enables you to build intelligent segments and Automations to reach your customers with the right message at the right time.