It seems dominating the ride-sharing industry just isn't enough for local tech giant, Uber. Now they're going after Postmates, too. 

On Wednesday, the company introduced the expansion of UberRush—the same-day delivery program the company's been piloting in New York will now make its way to San Francisco and Chicago too, with deliveries ranging from $5 to $7.

But don't think you can just hail an Uber and ask the driver to pick up some toothpaste on the way. There's actually very little interaction between the customer and Uber, besides paying for the trip, that is. 

Here's how it works: Participating businesses can sign up to have their goods delivered directly with Uber, or customers can access the service through e-commerce sites such as Shopify and Bigcommerce. Either way, you have to order the products through the store or restaurant's website, instead of via the Uber app. 

Uber will take a 25 percent cut of the delivery fee in SF, which is calculated based on distance, and the rest of the fee will go to the employee, er, independent-contractor-slash-courier.

Although the company has dabbled with new services before—such as its quick food delivery program UberEats—UberRush is Uber’s first attempt at putting its huge network of drivers to new uses.  

Uber said in a statement that it plans to target smaller, local retailers and restaurants instead of bigger brands, but, as Re/code suggested, this may be because larger brands such as Starbucks and Apple has chosen to work with Postmates instead. 

And just how will the new service fare in San Francisco? Well, on Tuesday, Postmates stole a bit of Uber’s thunder by setting its lowest delivery fee at just $2.50. In a city where you can get anything you want delivered any time, there's plenty of room for a little competition.