Many of the Directory API calls require a customer parameter referred to as the "Immutable id of the Google Apps account. (string)".
e.g. GET https://www.googleapis.com/admin/directory/v1/customer/customer/domains
I have no idea how to find/generate this for my Google Apps account. I am an admin.
Can someone point me in the right direction please?
I was able to find the customerId as follows
You will see URLs like this:
https://accounts.google.com/o/saml2/idp?idpid=Cxxxxxxxx
That Cxxxxxxxx is your customerId