ShackBurger on the chains new gluten free bun courtesy of Shake Shacks new gluten free bun courtesy of Shake Shack

Your thumb can score you a free Shake Shack burger today. That’s because the burger chain is celebrating the launch of its mobile ordering app with a giveaway.

Anyone who downloads the Shack App for iOS between now and Feb. 28 is eligible for a free ShackBurger (normally $5.55). Once you download the app, you’ll be prompted to use the promo code “shackappy” at checkout. The app allows you to find a nearby Shake Shack, schedule a pick-up time, and pay ahead of time for a quicker in-store experience.

Those with an insatiable obsession with the brand can also watch the live Shack Cam through the app. It’s a live feed of the original Shake Shack in New York City’s Madison Square Park.

There are several Shake Shacks in the D.C. area, including in Dupont Circle, Union Station, F Street NW in Chinatown, Tysons Corner, and Pentagon City. Shake Shack locations in ballparks and airports aren’t participating in the promotion. 

Also new to the chain are gluten-free buns ($1 extra) and pricey Prosecco ($15).