Shake Shack is giving away burgers if you download its app

Shake Shack pushes its mobile app to beef up sales

Shake Shack is celebrating the nationwide launch of its new mobile app by offering a free burger to anyone who downloads it by Feb. 28.

The app allows customers to choose their burger or shake of choice from an iOS device, before selecting a location and time for pickup. The burger chain began testing mobile ordering last year, in a bid to alleviate lines during busy hours.

"The app was developed to elevate the in-Shack guest experience, resulting in shorter pick up times and convenient mobile ordering," the company said in a statement.

In addition to mobile ordering, the Shake Shack app offers nutritional information, information on events and promotions, and links to the company's social media pages. Customers with dietary restrictions can also input allergens into the app and be warned about which items may contain the specified ingredients.

The company joins dozens of other restaurants using mobile technology to improve the in-store experience for customers.

The app is available only for iOS, though Shake Shack says that an Android version is in development. If you download the app, you can redeem your free ShackBurger by using the code "shackappy" at checkout before Feb. 28.