I may be asking an odd question, but webmasters seem like a decent place to post this.

I'm in the search for an accurate, easy API (such as using JSON or XML) so I can use my web application.

I've been trying Google's secret API, but it's dependency isn't that good because of parsing the string (weird JSON format that PHP sometimes return incorrect data or truncates the string due to parsing error, but Google's API is fair but can be improved.

So, all I'm asking is your current best currency API out there, I want to have them to include documented API so I can use it with PHP.

Cheers.