I would say the main difference is that ex_money is driven by the CLDR repository and therefore supports all defined 516 locales, all ISO4217 currencies; knows the correct rounding required for each currency (cash and transaction amounts) and knows how to format in a locale-specific way.

The second difference is the provision of an Ecto composite type for Postgres (and a lesser implementation for MySQL) to aid serialisation and preserve precision.

Of course none of these things may matter for a given application.

I’ve already expressed this on github, but I really really like the approach of going from a canonical source like cldr to implementing a money library. I’ve seen money libs include some json file with currencies and their iso codes and number of decimal places, but this only works for as long you won’t need to access this data elsewhere in your application. This is different with ex_money. I can explicitly include ex_cldr in my project and use the underlying data just like ex_money does and there’s no accidental miss-match or the attempt to keep multiple sources in sync.

There are few advantages:

• ex_money does support different currencies to be stored with it’s ecto.type.
• ex_money does support stringification based on the user locale a.k.a. “$ 1,000.00” vs “1.000,00 $”