OFX, a foreign currency exchange company, last week announced that its OFX Developers program has exited beta and is now open to all developers. OFX Developers offers a Payments API that gives developers 24/7 access to the global currency markets at rates more competitive than banks'.
APIs continue to work their way into just about every part of the digital economy. The latest example is Subledger, which offers a suite of APIs that let developers integrate accounting functionality into their applications.
Dwolla is an extremely innovative Payment API and the site allows you to transfer money with one of the least payment charges. We have covered Dwolla before here. Here is an interview with Michael Schonfeld, Developer Evangelist of Dwolla API.