For developers using OS X the Bloomberg API offers this Python library. OS X users should note that the OSX libraries are only compatible with OSX 10.7 and later, and can only be used with the Bloomberg Server API and B-Pipe data feed products (not the Desktop API). The Bloomberg API provides free, unrestricted access to raw financial data on current market trades (either real-time or delayed), reference data on historical information, and records of intraday trading. As part of their Open Market Data Initiative the library is offered under a "free-use" license, which allows unrestricted access to the interface's header files, documentation, and programming examples.
In preparation for this month's change to Automated Clearing House rules, Dwolla is updating its white label API to allow customers to opt-in (on a transaction by transaction basis) to an ACH option that specifies how a transaction should settle on the same day (provided other conditions are met).
Business models were nascent in 2005, when ProgrammableWeb listed only 105 APIs in our directory. There were only four basic models, according to John Musser's talk this morning at Glue. Fast forward six years and those same business models exist, but there's a lot more detail, as the now 3,000+ APIs have refined the ways an API can make money.
Royal Bank of Canada has launched a developer portal and set of APIs. The APIs can be used by eligible businesses and developers to add select RBC banking and services information to applications. Among the APIs are the Branch Locator API, Minimum Down Payment API, and the Amortization Schedule API.