I've used this hidden API in the past, but overall Yahoo's free finance API is much more accurate and developer-friendly. The output of this endpoint is format

I've used this hidden API in the past, but overall Yahoo's free finance API is much more accurate and developer-friendly. The output of this endpoint is formatted to be human-readable in such a way that it is annoying to do calculations with the result. For example, the result of converting 999 GBP to VND is "34.0263562 million Vietnamese dong." [1] So to make it useful, you need to parse "million," "billion," etc. as well as the nonstandard verbose currency name. For other results you need to parse the thousands delimiter, which is a space. The conversion is also inconsistent, which you can see by refreshing the result several times. This may be a cache issue on Google's end. The last problem is that it's missing some currencies such as the Pacific Franc (XPF). [1] http://www.google.com/ig/calculator?hl=en&q=999GBP=?VND http://www.google.com/ig/calculator?hl=en&q=999GBP=?VND