GET /v2/fx/rates returns available official rates keyed by quote currency. Countries sharing a currency share one key. It requires an API key and counts as one request. symbols filters quote currencies; base defaults to USD and can only be changed on paid plans.
curl
symbols=BRL; value and timestamps are samples:
400 invalid_format means the base currency is not published; 402 feature_not_in_plan means the plan cannot change it. A currency without a current official observation is omitted from rates.