Return your merchant balance in every currency you hold. Each balance
distinguishes between available (usable for new payouts), pending
(reserved for in-flight payouts), and total.
API keys are opaque strings prefixed by environment:
ak_live_* — production keys, accepted only on api.antonpayments.com.ak_test_* — sandbox keys, accepted only on api.antonpayments.dev.Include your key in the Authorization header: Bearer ak_test_....
Balances across all currencies.