Hanging on the wall of Postmates' stealth R&D laboratory, there's a framed photo of an iconic scene from Star Wars, Luke Skywalker bent down beside R2D2. Except someone has used Photoshop to replace Luke's face with Ali Kashani, Postmates' VP of Robotics. Nevermind that Kashani has never seen Star Wars (he considers this a point of pride). Kashani recognizes the symbolism of his face in a world where robots roll around next to people, where bots act almost like friends.

Kashani joined Postmates a year and a half ago, with a special mission to bring robots to the company. In the seven years since its founding, Postmates has been on the forefront of the on-demand revolution, averaging 4 million deliveries each month in over 550 cities. Now, it's turning its sights to something bigger: learning how to design and build its own delivery rovers inside Postmates X, its new in-house laboratory.

You can see this vision whirling around in the company's production garage. Postmates' rover, called Serve, stands about a meter high. It’s shaped like a child-sized shopping cart, with bright yellow paint. On top, a touch screen tells you it’s on the clock—“ON DELIVERY,” it says—and a flashing strip of LEDs around its body function as turn signals. Most noticeably, it has two big saucers for eyes, which blink, lending an uncanny resemblance to the animated robot WALL-E.

Phuc Pham

If you ask Kashani, Serve won’t replace Postmates’ fleet of human workers so much as it will economize their routes. Ninety percent of Postmates’ deliveries happen in cars, but more than half of them are within walking distance. When someone orders a burrito from a nearby taco shop, a Postmate usually hops in a car, sits in traffic, circles the block looking for parking—then has to repeat the process when they drop the delivery at the customer’s house.

“Somehow, as a society, we are OK with the fact that we are moving a two-pound burrito with a two-ton car,” says Kashani.

Serve is designed to fix that. Imagine: a fleet of them rolling into restaurants and convenience stores, picking up food, then hopping into a car with a human, who drives a few miles more before sending Serve to bring the delivery the last mile to reach a customer, who unlocks the cargo by using the touch screen or their mobile phone.

'There's this perception issue, this dystopian view. We have five seconds to change people's minds.' Ali Kashani, Postmates VP of Robotics

Postmates will soon begin rolling Serve into its key markets, starting in Los Angeles, where mayor Eric Garcetti has been exceptionally welcoming. But Kashani likes to think about how, if they get it right, the rovers could become so much more than just take-out couriers. It could deliver medication. It could fight crime. It could pick up the day-old bagels from a bakery and ferry them to a food bank, helping to eliminate food waste. It could roam around developing accurate maps of streets and sidewalks and cities. “It could patrol the neighborhood," says Bastian Lehmann, Postmates' co-founder and CEO. "Or you could use it for evil things, like it could write parking tickets."

It's a heroic view of what the team here is building, and one that makes Postmates X feel less like a robotics R&D lab, more like a bid to save the world. But first, Kashani likes to remind himself, they have to figure out how to deliver burritos.

In the delivery world, robots have come to represent both a holy grail and an inevitability. Replace some or all of the human labor and you get faster drop-offs, more pick-ups per hour, and cheaper goods for everyone. Big companies, like Uber, Amazon, and Alibaba, have each invested heavily in developing such technologies, from delivery drones to autonomous bots; venture capitalist have poured millions into delivery robot start-ups like Marble, Boxbot, and Dispatch, all of which want their piece of the robo-delivery future. By some estimations, sidewalk bots like Serve will make up 85 percent of last-mile deliveries by 2025. Whichever company gains a foothold now will have a huge advantage in the future on-demand economy.

Its touchscreen shows when the rover is on delivery, and lets customers unlock their cargo. Serve uses a combination of lidar, sonar, computer vision, time-of-flight cameras, and GPS to navigate the world. Phuc Pham

But building an autonomous sherpa is no easy task. Take the challenges of self-driving cars, then add a few sidewalk cracks, curbs, pigeons, piles of trash, popsicle stands, and—worst of all—people, who are historically hard for robots to understand. A delivery robot has to fit into the elaborate choreography of public space, picking up on the subtle cues pedestrians give when they want to turn or stop or walk a little faster. And then, it also has to signal to cars when it’s entering a crosswalk, navigating streets more like a self-driving car.