For reviews of most businesses, there’s Yelp. But once you pass beyond that magical threshold known as the airline check-in counter, you enter a bustling world of commerce not typically covered by Web sites.

On Monday, GateGuru, an application for the iPhone developed by Dan Gellert, a former associate in Time Warner’s venture investment group, set out to solve that problem. The software is targeted at the airport-hopping road warriors like the character George Clooney plays in the new film “Up in the Air.”

“Despite there being $6 billion in annual spending at airports and a billion hours spent within the top 85 airports alone, there’s nothing to help people navigate the airport marketplace,” Mr. Gellert said.

GateGuru takes a direct feed from the top United States airports with information about all of their bookshops, restaurants and other concessions, both before security and after, and then it asks users to submit reviews. A version for $1.99 in Apple’s App Store allows people to navigate the nation’s top 85 airports; a free version lets a user pick two airports.

With the app only live for one day, reviews are only now trickling in. For example, a user named Joeme writes that the fare at the cocktail lounge Ozone-Bos in Boston Logan’s B terminal “is about as good as airport food gets” and gives the establishment four stars.

In Terminal 4 of J.F.K. in New York, Mr. Gellert himself gives the KFC Express one sad star: “So subpar unfortunately. Hit the McDonald’s or something post-security.”

Mr. Gellert believes that as airlines cut back on in-flight service, more people are spending time and money in airports and are looking for a guide like GateGuru. “You have a captive audience. If they provide them with decent amenities, they actually do spend money.”