Bedrock Billing per Customer

Hi. I'm developing an application that uses some Bedrock Services. The initial idea was to create a service key for each customer that will use this application, in order to be able to track all the consumption. However, i'm not finding any way to do that. The question is: Considering that each customer could have a key, and this key will be used in a application (on-premise), how can i track this key consumption? Which approaches can i follow to achieve the expected behavior? I would like to access my company board and be able to access billing track of each customer that i've.