Facebook is adding a payment feature to its Messenger app that will allow users to link their debit cards to the service and send money to friends. The instant payment system, known as peer-to-peer payments, will allow money to be exchanged just as easily as a photo, a text or a smiley face.

The system would be only for peer-to-peer payments, and does not offer the ability to make purchases in a store, such as is possible with Google Wallet or Apple Pay, or through the use of a credit or debit card, or PayPal. However, Facebook is already experimenting with using a “buy” button to purchase items advertised on its site.

To send money to another, users simply tap the “$” icon and put in the amount. A Visa or MasterCard debit card will need to be added the first time money is sent or received, and a PIN will need to be created.

A number of peer-to-peer money transfer services, such as Venmo and Square, have begun to appear in the U.S. However, Facebook’s Messenger app is one of the world’s largest platforms, with over 500 million monthly users. Wall Street is hotly anticipating the new functionality.

Facebook says that it is trying to simplify the process as much as possible. They want to keep the conversation and the payment in one message thread that will serve as a record of the transaction. Right next to the thumbs-up button on the messenger screen, a dollar-sign icon will appear. If a debit card number is already set up in the app, money can be sent to the other person in the conversation through a click of the icon.

The money goes directly from one bank account to another because debit cards are used to handle the transfer. Facebook’s Steve Davis, the product manager in charge of the new project, says that users do not have to remember to withdraw the funds later, such as is required by PayPal or Venmo.

The feature is expected to become available in the next few months at no charge to users. It will be available on iOS, desktop and Android.