Handling ISO Currency Codes in Software

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Quick Answer: When processing financial transactions over the internet, systems cannot rely on ambiguous symbols like the dollar sign ($) because dozens of countries share it. Instead, banking APIs use ISO 4217, a global standard that assigns a unique three-letter code (like USD, CAD, or AUD) to unambiguously identify every currency. If you were to write "$129" in a text message, your friend probably knows exactly what you mean based on where you live. But if you send "$129" to a banking API, you have a problem. Think of currency symbols like local time zones.

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