> I'm guessing customer IDs are associated with e-mail addresses? They are (on Let's Encrypt's end), if an email address was provided. It's a 1:n relation, th

> I'm guessing customer IDs are associated with e-mail addresses? They are (on Let's Encrypt's end), if an email address was provided. It's a 1:n relation, the same email may be used for any number of ACME accounts. Roughly speaking, for most clients, the ACME account maps to a specific ACME client on a specific host. If you run three servers with separate ACME clients, you're probably using three ACME accounts (even if you're using the same email and issuing certificates for the same domain). Large or custom implementations may reuse the same ACME account across many servers and domains. (Issuance would typically be centralized and operated as a separate system in these scenarios.)