US coffee chain Starbucks has refreshed its popular iOS payments app with a tipping feature and the ability to pay with a shake of the handset.

The new additions are designed to keep up the momentum in mobile payments, an area where Starbucks is a pioneer.

Adam Brotman, chief digital officer for the coffee chain, said “more than 11 per cent of transactions a week” in stores now occur with a mobile device. Plus nearly 10 million customers currently use Starbucks’ mobile app.

From March 19, US customers will have the option of leaving a tip via their iPhone app in increments of $0.50, $1 and $2. The feature will be available in 7,000 out of 11,000 Starbucks stores in the States.

In addition, customers can bring the barcode of their Starbucks Card, which is used for payment, onto their smartphone screen more easily just by shaking the mobile device.

An update for the company’s Android app, including tipping, is expected later this year.