> Use integers to represent financial amounts

I followed this mantra when building a trading system. This was the worst engineering decision I ever made - it added complexity and runtime overhead, plus readability was reduced when debugging.

If your language has a proper decimal type like BigDecimal in Java or Decimal in Swift, I'd suggest using it. They offer perfect precision for financial applications, are battle tested and are a natural way to represent financial amounts. Yes, Java BigDecimal is unweildy, but it works.

If you're using JavaScript however, definitely use integers to represent financial amounts.