“The system can’t handle a billion dollars”

CLDR currency definitions

The home of the Unicode Common Locale Data Repository

Falsehoods about IBANs

Generate, parse, validate, error-correct and present IBAN (and IIBAN) bank account information in PHP.

tax

A PHP 5.5+ tax library.

Twenty five thousand dollars of funny money

Same error as above at Google Ads, or the danger of separating your pennies from your dollars, where $250 internal coupons turned into $25,000. My advice: get rid of integers and floats for monetary values. Use decimals. Or fallback to strings and parse them, don't validate