It's Thursday evening and your friends want to grab dinner after happy hour. If you live in one of the seven cities it currently serves, you can simply open the Reserve concierge dining app, tell it what you want--say, an 8 p.m. reservation for seven people, Mediterranean--and it will tell you what's available nearby. Reserve makes dining recommendations, books your table, automatically pays your bill, and even lets you split the check—all without the hassle of picking up the phone or flagging down a server. Users pay a flat $5 fee to Reserve for each completed reservation, and restaurants are not charged for partnering with the app. Plus, Reserve uses required, private reviews to tweak recommendations and boost its restaurant relationships. Since the app launched at the end of 2014, the company has more than doubled participating cities and acquired no fewer than three companies: online reservation service Zurvu, payment tech company Hail, and restaurant guest management company Set for Service. There is real confidence in the company's ability to expand; it raised $15 million last year from several investors, including Uber co-founder Garrett Camp's start-up incubator, along with celebs Will.i.am and Jon Favreau.