What is the rate source and update frequency?

Rates come from Frankfurter (ECB) and update daily (~00:05 UTC).

How are decimals and rounding handled?

Follows ISO 4217 (e.g., JPY=0, USD=2, KWD=3). Default rounding is half-up.

From

USDUS Dollar

EUREuro

JPYJapanese Yen

GBPBritish Pound

CHFSwiss Franc

CNYChinese Yuan

HKDHong Kong Dollar

AUDAustralian Dollar

CADCanadian Dollar

NZDNew Zealand Dollar

SEKSwedish Krona

NOKNorwegian Krone

DKKDanish Krone

SGDSingapore Dollar

KRWSouth Korean Won

INRIndian Rupee

BRLBrazilian Real

MXNMexican Peso

ZARSouth African Rand

TRYTurkish Lira

KWDKWD