You can now place your Shake Shack order from your phone -- and if you do, your first burger will be free.

The beloved fast-food chain is giving out free single ShackBurgers to every guest who downloads the new Shack App and uses it at stores nationwide (except at airports, stadiums or ballparks).

To participate in the app-y hour deal, customers need to download the app, create an account and use a promo code at checkout: "shackappy." The freebies will be available through Feb. 28, and only for first-time users of the app. 

The app was being tested in certain locations but is now available for use at stores nationwide on iOS phones, according to the company.

“The Shack App brings a whole new way to experience Shake Shack for our guests -- meeting them where they are, when they want, on their terms,” Randy Garutti, CEO of Shake Shack, said in a statement. “Our initial test and rollout have gone very smoothly, and I am thrilled to share that you can now order ahead at nearly all of our U.S. Shacks.”

Wait times at Shake Shack can be legendary, but the app is designed to make picking up your food easier: You can choose your meal, select an available time to pick it up (times are available in 15-minute increments) and, if all goes according to plan, arrive to find your food ready to go.

The app will also allow you to find your closest Shake Shack, keep track of your orders or your food allergies, find nutritional information (pro tip: don't look, it's too depressing) and even check out those long lines by watching the Shack Cam at the original Madison Square Park location.

Android users are out of luck for the moment, but the chain says an app for that platform is in development.