If you’re sick of carting people around as an Uber driver, Amazon is now offering to pay you to deliver packages.

Amazon Flex, a mysterious service that was first spotted in the Seattle area last month, is now going live. Amazon says it’s currently available in Seattle, and will soon expand to Manhattan, Baltimore, Miami, Dallas, Austin, Chicago, Indianapolis, Atlanta, and Portland.

So, what is Flex? It’s the Uber for Amazon. Or the Amazon for Uber. Or something like that. Amazon says you can make $18 to $25 an hour delivering packages.

“Be you own boss, deliver when you want, as much as you want,” says Amazon.

If you sign up to be a Flex driver, you’ll need to pass a background check. You’ll also need to own an Android device, as that’s where the Flex delivery software will be housed. You also need to be at least 21 years old and have a valid driver’s license, of course.

“You can choose any available 2, 4, and 8 hour blocks of time to work the same day, or set availability for up to 12 hours per day for the future. You can work as much or as little as you want,” says Amazon. “You can pick up deliveries at a location near you. You’ll receive items to deliver in a local radius, based on length of the delivery block you signed up for.”

For now, Flex drivers will only be delivering Amazon Prime Now packages – the company’s hour-delivery service. Amazon says that “in the future, you may deliver other types of Amazon packages as well.”

This is Amazon’s first big step into this fast-growing element of the economy. The company must know that there’s a good chance it will face some of the same issues companies like UBer face, as questions of whether drivers are employees or contractors will inevitably arise.

And with this new service, don’t be shocked when your Uber driver asks you to get in the backseat. His front seat might be filled with Amazon packages.