Only block the "/support/new" call behind ecash Each successful redemption will return a response containing a new ecash token Turn ecash into jwt to track / meter things once consumed Either of those three ways would accomplish something I do find special about using ecash as an API token: cuts off source of identity from the original acquisition of the ecash, even if you need to associate after first consumption.
Ecash is perfect for this. You don't even need to recycle once. If you buy it with a payment (or some other "proof of humanity" or something), you can use it immediately (and privately). Ecash systems without the ability to transact between users definitely has applications people are interested in (such as resource access control).