Apple is expected to announce a new Apple Pay rewards program at the Worldwide Developers Conference in San Francisco next month, according to sources familiar with the company’s plans. The scheme hopes to encourage customers to use Apple Pay on a regular basis.

The rewards program will offer “perks to consumers who make purchases with the service,” reports The New York Times, citing two sources who have been briefed by Apple. However, specific details about those perks are yet to be revealed.

An Apple Pay rewards program has been the subject of speculation since the service was announced, and the rumors hotted up earlier this month when it was revealed that Apple was interested in acquiring the failed payment rewards startup Clinkle.

Some Apple Pay competitors, such as CurrentC, already offer rewards programs that keep customers interested in the service, and help fend off competition. A good Apple Pay rewards program could make it harder for rivals like Google and Samsung to compete.

The same NYT report says Google will announce its own Apple Pay competitor, called Android Pay, at Google I/O later this week. The service is expected to be very similar, and could offer a rewards program from the very beginning — as well as the ability to send money to other Android Pay users.

While Apple could make its rewards program official at WWDC on June 8, it probably won’t launch until later this fall — perhaps alongside iOS 9. Even then, it will almost certainly be exclusive to U.S. customers for some time, just like Apple Pay itself has been since its debut.