WhatsApp launched its digital payments service in Brazil while the messaging app capitalizes on its popularity in emerging markets.
The move comes as the parent company Facebook advances with plans to bring more e-commerce to its platforms.
WhatsApp Pay allows users to exchange money for free or make purchases from small businesses.
In January, CEO Mark Zuckerberg outlined plans to offer the service in India, Indonesia and Mexico.
On his blog WhatsApp he pointed out that the launch was part of a wider digital payment strategy on all Facebook platforms.
“Since payments on WhatsApp are enabled by Facebook Pay, in the future we want to allow people and businesses to use the same card data in the Facebook family of apps.”
While person-to-person payments will be free, small businesses will have to pay a “processing fee to receive customer payments,” says the blog.
WhatsApp has 120 million users in Brazil, making the country its second largest market after India.
The company has already experimented with the payment service in India, where it has 400 million users.
However, the company’s efforts to launch WhatsApp Pay in India have been suspended for two years by regulators.
In April, Facebook announced that it had acquired a 10% stake in the Indian telecommunications group Reliance Jio for $ 5.7 billion (£ 4.5 billion).
This deal gives Facebook a powerful ally in Reliance Jio president Mukesh Ambani, who is Asia’s wealthiest man.
The two companies intend to focus on a partnership with the newly launched JioMart e-commerce platform.
Last month Facebook invested an undisclosed sum in the Gojek app, based in Indonesia.
Companies will use the bond to expand Gojek’s GoPay digital payments service.
Facebook bought WhatsApp for about $ 20 billion in 2014. In February, the messaging service said it had over 2 billion users worldwide.