The Facebook-owned company is believed to be trialling a digital payments system called "WhatsApp Payments" that could launch in the UK in the coming months.
See also: Scamwatch: new WhatsApp fraud
See also: Whatsapp 'to link a billion people'
It was spotted in beta form in the latest update to the messaging app, which currently has over one billion daily active users. According to WABetaInfo, which published a screengrab showing the feature, it appears to only be available in India at the moment.
The WhatsApp Payments feature that could soon be coming to the app
Sending instant payments is already available on Facebook Messenger, but adding it to WhatsApp could make it even more popular.
The idea is that small amounts of money - for a taxi fare or round of drinks - could be quickly and conveniently sent between friends.
It also means that techy users will have another way of emptying their digital wallets without having to leave the house.
It could also help stop the spread of WhatsApp scams that attempt to trick people into providing their bank details to strangers.
One scam takes the form of an official-looking message that warns people their "trial service" of the popular instant messaging app is coming to an end.
"Our records indicate that your WhatsApp trial service is exceeding the one-year period," it reads.
"At the completion of your trial period your WhatsApp will no longer be able to send or receive message [sic]. To continue using WhatsApp without interuption [sic], we need you to subscribe for any of our subscription periods."
The message then provides a link to a "customer portal" where an unwitting victim can provide their bank details.
Action Fraud, the national fraud and cyber crime reporting centre says the message is a clever way to dupe people but that users should be vigilant.
"Long term users of WhatsApp will remember paying a 0.99p annual fee to use the messaging service. In 2016, this was scrapped by Facebook who took over running of the company after buying it for £11.4bn," the organisation said.
"That means since 2016, the service has been free for every user."