The two companies have also partnered to offer free delivery until December 17.
shake shack and postmates
Credit: The Washington Post / Getty Images

What’s better than a free hamburger? A free good hamburger, of course—so fans of Shake Shack will want to hear this offer. The beloved burger chain has teamed up with delivery service Postmates to give away free ShackBurgers from now until December 17 for both you and a friend (assuming your friend is not already a Postmates customer).

To promote Postmates delivery partnership with Shake Shack, the two companies are offering two deals this week. First, until Sunday, all delivery fees are being waived on Shake Shack orders. But second, the brands have also launched a refer-a-friend campaign featuring a credit for a free burger as the reward. Current Postmates users need to refer the service to a new user. That new customer then must enter a promotional code provided by whoever referred them. But once that person’s first order is complete, both parties get a $10 credit that can be applied towards ordering a future ShackBurger. (Additionally, both people need to live within the delivery range of a Shake Shack, so the promotion only applies to Atlanta, Austin, Baltimore, Boston, Chicago, Dallas, Houston, Las Vegas, Los Angeles, Miami, New York City, Orlando, Philadelphia, Phoenix, San Antonio and Washington, D.C.)

A spokeswoman for Postmates said that these kinds of referral programs are common for the company, but not as a tie-in with Shake Shack. “Sometimes it’s $10, sometimes it’s $100 in delivery fees. The offer changes fairly regularly,” she told Nation’s Restaurant News. That site also points out that this is not Shake Shack’s first app-related burger giveaway. When the brand launched its own app at the beginning of this year, it offered a free ShackBurger to anyone who downloaded it. That promotion reportedly resulted in 90,000 in free burgers, proving that free Shake Shack can certainly work as a motivator for new users.

“We’re thrilled to team up with an iconic brand like Shake Shack to bring our customers even more of what they want on-demand,” Russell Cook, Postmates’ senior vice president of operations, said in a statement. “Shake Shack’s menu has developed a cult following from coast to coast, so we’re excited to let our customers share the Shake Shack love with their friends and family.” Let’s just hope your friends and family aren’t very tech savvy and have never used Postmates before.