Financial giant Citi has set up an open platform giving software developers and financial technology (fintech) firms a "sandbox" in which to test their solutions.

The Global API Developer Portal was launched by Citi yesterday, as the global bank seeks greater efficiency in its collaboration with external innovators. API, or application programming interface, is a toolset that allows a user to test how a new solution or application works within a bigger system.

In Citi's case, a portal user can gain access to the bank's APIs in areas including account management, peer-to-peer payments, money transfer to institutions, Citi rewards, investment purchases and account authorisation.

"The rapid pace of technological change demands transformation from the inside out and the outside in," Citi global consumer banking chief executive Stephen Bird said yesterday when announcing the portal.

Prior to yesterday's launch, Citi's API had already helped Singapore online concierge and delivery firm honestbee to develop a feature that allows clients to apply for the Citi Cash Back card on honestbee's website and phone application.

A wider use of APIs has been highlighted by the Monetary Authority of Singapore as a key part of the nation's fintech agenda, as it means development of new innovation can be more nimble and better integrated into existing banking systems.

"This will encourage open collaborations with the fintech community and potentially deliver better financial services for customers," said MAS chief fintech officer Sopnendu Mohanty yesterday.

Other banks have also made progress on this front.

OCBC launched an open API platform in May, while UOB started using API in 2014, reflecting the tech competition heating up across the industry.