Jack in the Box and Postmates have partnered to bring on-demand delivery of Jack in the Box’s entire menu to Postmates customers, any time of the day. Delivery of Jack in the Box is available from more than 1,000 restaurants in 28 of Postmates’ U.S. markets.

To celebrate the launch of this partnership, from March 25 to March 31, Postmates customers can score a free Jumbo Jack by getting a friend to try Jack in the Box via Postmates delivery. Plus during this time, Postmates customers can also try their favorites from tacos to curly fries with free delivery.

“With a menu that’s packed with variety, Jack in the Box prides itself on being able to serve guests whatever they crave, whenever they crave it,” says Iwona Alter, chief marketing officer at Jack in the Box. “Now, we are excited to satisfy guest cravings whereever they may hit by joining forces with Postmates and its expansive on-demand delivery fleet.

“We want to give our fans the opportunity to celebrate this partnership by sharing and enjoying some of our most classic menu items with their family and friends,” Alter adds.

To participate, customers must download and open the Postmates app on iOS or Android, and click on “Invite Friends.” There, they will see a referral code that they can share with their friends and family members. A friend has seven days to use the code for a free Jumbo Jack and regular fountain drink. Once the friend uses the code, the referring customer will receive a credit in his or her Postmates account for a free Jumbo Jack (valid for the next seven days).

“We’re thrilled to team up with an iconic brand like Jack in the Box to bring our customers even more of what they want—on-demand,” says Dan Mosher, SVP, Merchant Lead, Postmates. “We’ve been delivering Jack in the Box for years, but by entering into an official partnership we look forward to working closer with them to create an even better customer experience.”