With same-day delivery services becoming more popular by the day, Postmates has a unique market they’re increasingly noticeable in. The third party delivery service is now expanding to Washington, DC, their fourth city. In addition to spreading to one of the nation’s largest markets, they’ve released an Android app.

While still in beta, the app allows for use in any of the four cities Postmates is in: Seattle, San Francisco, Manhattan/Brooklyn, and now Washington, DC. Potential users will also have to join a Google group for the service, and register as a tester. For the uninitiated, Postmates acts just like you want it to — order from area businesses, and Postmates has your wares to you in about an hour.

The service is up against stiff competition from the likes of Google and eBay. With Google focussing their efforts on the San Francisco area, Postmates has some time to grow their service. They could be thwarted from massive gains, though; most larger retailers are either on-board with bigger name services, or are testing their own.

Postmates notes that when they go live in DC, they’ll have 200 couriers at the ready. That’s a big swathe to cover, and it seems as though Postmates has their bases covered. We hope they can grow as quickly as they can deliver, too. We like a good undergo story.