Sendgrid subuser api domain field

Question

In the subuser api of sendgrid :

http://sendgrid.com/docs/API_Reference/Customer_Subuser_API/subusers.html

you can see that the last parameter is mail_domain which is optional. I want to register a mail_domain for the subuser. It says : A mail domain must already be setup with SendGrid, please contact support@sendgrid.com to have one setup

My questions are :

1) What is the procedure for getting mail_domain for subuser.

2) If I do not register a mail_domain for subuser can I later assign a mail domain to the subuser?

Answer 1

Finally spoke to the support team and figured out.

1) You need to fill the webform for white labeling the domain.

2) Yes you can whitelabel the domain anytime later. If you do not provide a mail_domain, it will assign sendgrid.com as the domain.

Answer 2

When setting up a Subuser, you're required to whitelabel it, either to an existing whitelabeled domain (which you can do via API or UI), or by registering a new whitelabel (which can only be done in UI). You cannot create a Subuser without a whitelabel.