The company’s popular mobile payments app Venmo processed a record $6.8 billion in the first quarter, double the amount from the same period last year.

Venmo, which lets users send money to each other instantly, much like PayPal’s core service, has been among the crown jewels in PayPal’s payments portfolio. It acquired the service, which is popular with younger users, three years ago as part of its $800 million acquisition of payment processing startup Braintree.

People tend to use Venmo for small, cashless transfers, like reimbursing a friend for dinner, paying a babysitter or for paying their share of the rent.

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Although Venmo is growing quickly, it’s unclear how much impact it has on PayPal’s financial results. It was only last year that PayPal started generating revenue from the service by letting merchants accept Venmo as a payments option. Merchants pay a small fee for each transaction. Although he declined to get into specifics, PayPal’s chief financial officer John Rainey said during an earnings call on Wednesday that the company expects a “steady” increase in revenue from Venmo.

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Overall PayPal saw significant growth in mobile payments volume, in line with one of the company’s strategic goals since spinning off from former parent company eBay (“EBAY”) in 2015.

During the first quarter, payments made through mobile devices increased 51% from the same period last year to $32 billion. They accounted for nearly one-third of an overall $99 billion in payment volume for the company.

PayPal may have the potential for even more mobile payment growth. Last week, the company announced that it would become one of the mobile payment services available to users of Android Pay, Google’s (“GOOG”) digital wallet for Android phones, turning two major payment rivals into partners.

Shares of PayPal rose 6% to $46.96 in after-hours trading on Wednesday.