Where can I find information on a large number of "exchange" or "trading platform" APIs showing which currencies (digital and fiat) they convert between?
Hi user41634, I just edited your question's title in order to better capture the question's intent. Should you disagree with what I did, feel free to change it to your liking or rollback. The second part of your question seemed fairly unrelated, so I removed it, to give your question a clear focus. If you can think of how to ask that without inviting discussion as it was before, you might want to ask that as a new separate question.– Murch ♦Feb 2, 2014 at 13:50
Since you originally stated that you wanted to write a trading bot, perhaps you will find the following library useful:
"XChange is a Java library providing a simple and consistent API for interacting with over a dozen Bitcoin exchanges providing a consistent interface for trading and accessing market data" (according to their GitHub page)
Unfortunately, I cannot tell you more about it, as I just stumbled upon it by accident.
Each site has its own set of apis and documentation, I don't think it's likely that you'll find a single site with a complete set of APIs.
Here are some links to get you started:
Are such APIs for free? Jun 30, 2017 at 15:23
The API is usually free (I am looking into Coinbase/GDAX), but you are charged a fee at every trade. Also note, some of the above are N/A any more...– mBardosDec 28, 2017 at 17:02
Multiple links have been removed because they were linking to broken or domain parking services. Please consider adding new links to make this answer more useful.– Murch ♦Feb 22, 2018 at 1:25