Facebook Messenger users could soon be able to send each other money using the platform, just as they would a photo.
According to screenshots taken using the iOS app exploration developer tool Cycript, the feature is already in place, but has yet to be activated by the social network.
Users will be able to add a debit card in Messenger or use one already on file with Facebook, while an in-app pin code offers increased security. It is not clear if the payment service will be free-of-charge or if Facebook will charge a small fee.
While unexpected, the decision to turn Messenger into a potential e-commerce platform is likely to have been influenced by the appointment of former PayPal president David Marcus as head of Messenger.
The code for the payments platform was first discovered by security researcher Jonathan Zdziarski last month, before Stanford student Andrew Aude investigated the feature further.
Aude told TechCrunch that users simply enter an amount and press send and Facebook does the rest. He also confirmed that the transaction remains private and nothing is published to the user's News Feed.
Currently, the service only works with debit cards, not credit cards, presumably because money transfers are cheaper to process from debit cards and the service being provided is, at the moment at least, free to use.
The payments are also only possible between individuals, but a note in the code does confirm that "multiple payment attachments will be supported in the future."
If Messenger's payment service is successful then it could be a major boost to Facebook in the battle to dominate the messaging app industry. The social network is currently competing against Apple's iMessage, WeChat, Google Hangout as well as dedicated payment apps such as Venmo.
While it could be some time before members of the public gain access to the payments feature, Facebook seems to be making a clear transition from social network to service provider. Last month it was also revealed that Facebook is implementing a buy button for e-commerce purchases, something which ties in with today's news.