Cryptsy offers bitcoin and digital currency trading services. The Cryptsy Node.js library created by Ek Palmer contains an illustrated example to demonstrate a list of all markets that participate in trade events. What the API does for users is to allow the query of general market data and orderbook data. Additional information such as market data, transactions, and execution of trades is available with authenticated methods.
As PSD2 starts to take shape in Europe, ING has published three new open banking APIs in France. The APIs include an Account Information API, Payment Initiation Services API, and Confirmation of Availability of Funds API. This is a starting point, and ING is working on additional APIs soon to come.