HSBC in the UK and Australia's NAB are both entering the API game by opening developer portals that give third parties access to some of their data.
HSBC has acted quickly to meet the UK Competition and Markets Authority's decision to require big banks to open up certain data via APIs by the end of the first quarter of 2017.
The bank has so far made three APIs available - for branch and ATM locators as well as a product finder - which are CMA mandated as part of an effort to help smaller providers and new entrants take on the high street giants and force them to work harder for their customers.
In the longer term, by early 2018 HSBC and others, such as Barclays and Lloyds, will have to deliver new APIs that will allow personal customers and small businesses to share their data securely with other banks and trusted third parties.
Says the bank: "This is nothing short of a revolution in banking and will change the face of financial services forever."
Meanwhile, NAB says that later this month it will become the first major Australian bank to launch a developer portal.
Beginning as a closed beta, the portal will start with two APIs: for branch and ATM location, and foreign exchange rates. Developers approved to take part in the beta will be able to plug into the NAB data for testing and possible integration to their own systems.
Antony Cahill, COO, NAB, says: "With the rise of the digital age and evolving customer expectations, APIs have become core to banking infrastructure to enable rapid deployment of various functions across multiple channels to meet those customer needs and quickly keep pace as those needs evolve.
"Our API strategy is based on three key streams of customer enablement, partnership arrangements and open API categorisation which this portal will be an integral part of.
"We are collaborating with a number of partners to both provide and receive data leveraging API technology including Xero, MYOB and VISA. We want to keep building our ecosystem with likeminded organisations to allow us opportunities to innovate and improve our experiences for customers."