Regarding ACH/E-Check transactions. Will something need to be configured or will I need to generate a separate set of credentials generated? The anticipation is that all merchants will be set up to accept ACH.
If you want to set up an Application to accept ACH you can make this API call: https://finix-payments.github.io/finix-admin-docs/#step-3-enable-a-processor. Alternatively, since you want all Merchants to accept ACH, we can make that the default configuration for your entire platform.