The days of showing up at a popular bar only to have to wait in line or be turned away to wander the Hub streets, looking for some place else to drink, are over.

SceneTap, a free app which launched in Boston last week, lets bar-goers plan a night out on the town before even leaving the house.

Using real-time technology through partnerships with some of Boston’s most frequented watering holes, SceneTap tracks the amount of people in a given location and allows customers to scan the scene on their smartphones prior to arriving at a destination.

“The technology we use is basically designed to count the number of people that walk into any given room and pick up their gender and their age,” said Andrew Nieman, director of Business Development for SceneTap.

Nieman described the app as a mix of Facebook and Yelp.

“The intent is to bridge the gap between something you get on Facebook, where you can preview places, and Yelp, where you can get reviews,” he said.

Through an “invisible trip line” and “facial detection” at the entrance of specific clubs and bars, SceneTap captures information, like whether you are male or female, and reports it back to a customer’s phone in real-time. Users can then check the male to female ratio at those bars, and get a general age range.

While some cities, like San Francisco, weren’t initially receptive to the new technology, Nieman said unlike “facial recognition,” the device they use is completely anonymous.

“It’s something commonly used in big box retail spaces like Wal-Mart and Target, “ he said.

SceneTap first started in Chicago in 2011, and Boston is the first East Coast destination for the company to launch in.

“It’s a great city with a great bar culture and we always knew we would launch here before even New York City,” said Nieman.

From Fenway Park, to the Back Bay and Faneuil Hall, SceneTap has been working with more than 20 bars in Boston, including Dillon’s, Clerys, Jose McIntyres, the Greatest Bar, Paddy O’s and The Place.

“We have got a really good spread,” said East Coast Regional Business Development Manager Michael Kalil, adding they also reach hot spots in the Chestnut Hill area.

In order for customers to gauge what the atmosphere is like at a specific destination, the SceneTap app uses several color-coded categories to let bar crawlers know what to expect before going out.

A “Hot Spot” is the more crowded bar, which is anywhere from 80-100% full. For those looking for a little more elbowroom, a “Hoppin’” bar is measured as 53-100% full.

If it’s a night where you don’t feel like getting too rowdy, but still want a place to meet new people, perhaps it’s wise to pick a “Lively” bar, which is at 22-52% capacity, according to the app’s measurements.

Lastly, those looking to wind down with a drink can head to the bars that are listed as “Chill,” or 0-21% full, on SceneTap.

“There is something for everyone,” said Kalil. “From those who want a relaxing night, to those who want to rage.”

The app also gives you the distance between bars on a map, so customers know exactly how long of a walk—or cab ride—it is to the next place.

Kalil, who has worked in the bar industry prior to taking on SceneTap’s Boston market, said the app benefits both bar owners and bar customers.

“This is the kind of information we would have loved to have had because we would have to record all of these analytics to see how good our advertising and promotions were,” he said. “Now, SceneTap services allow [bar owners] to look back and see what was going on on a particular day so they can plan ahead.”