Liquid Template Variables - customer
From Spiffy Stores Knowledge Base
The Customer object is available in order notification objects and in the Checkout Additional Content & Scripts section.
Reference
customer.email
Returns the email address of the customer.
customer.name
Returns the full name of the customer.
customer.metafields
Return the metafields for the customer.
Metafields can only be managed using the Spiffy Stores API.