Whether you are looking to find a co-founder for your start-up, connect with a potential investor or hire a college intern, there's an app for that.

Smartphones are changing the business-building game for entrepreneurs. With a few taps or swipes, introductions are brokered, coffee cups shared and an ever-widening circle of connections made.

LinkedIn, with more than 313 million people registered on the site, commands the professional networking sphere, and in the past year it has released a series of apps for the smartphone and tablet. But they're not the only mobile tools that can help you mingle or strike up that first conversation.

The answer to business networking via smartphone isn't adding connections through Faceboook or Twitter, either. In fact, the app ecosystem being developed for entrepreneurs is looking a lot more like popular dating app Tinder than any of the staid social media models. And many of the latest networking apps make use of LinkedIn and other social media data, precisely so you don't have to directly access LinkedIn or other social media sites yourself.

Check out these 8 under-the-radar networking apps to help boost your presence on the scene and meet those who can help you achieve your goals. As they say in business, it often comes down to who you know, not what you know.

—By Ellen Lee, special to CNBC.com
Posted 25 October 2014

Tinder meets business networking in this professional matchmaking app. Just as with Tinder's popular dating app, on Weave you swipe through professional profiles and look for the ones that catch your interest. When two people both indicate they want to meet, the app connects them. The app's algorithms try to show the profiles most likely to match your criteria, and it claims to facilitate more than a hundred meetings a day.

Brian Ma, formerly the co-founder of Decide.com, which was acquired last year by eBay, was inspired to develop the app last year when he was trying to establish himself as an angel investor. He attended networking events and asked his friends to make introductions but figured there had to be a better way. "I knew there were good people around me that I should be meeting, but we couldn't find each other," he said.

And it's worked for him. He met three investors through the app, who have since funded the San Francisco-based start-up, and he hired the start-up's first five employees (and counting) through the app. Whenever he has downtime—at the airport, at a bus stop, at home—he flips through the app's latest profiles. "It makes it so easy," he said. "I can literally swipe away for five minutes."

Available: Android and iOS

Aimed at the millennial generation, Coffee the App can be described as another Tinder-inspired professional matchmaking app. Using LinkedIn or Facebook to sign in, you swipe from profile to profile, moving your finger to the left to pass and to the right if you are interested in connecting. If there's a match, the app makes an introduction.

If you need to hire an intern or entry-level employee, you can post a job on the app and search for candidates. Young professionals can also use the app to network with other young professionals.

Available: iOS

Caliber helps professionals in the technology industry connect. Once you sign in with your LinkedIn profile, you designate your role, such as engineer, product, business, founder or marketing. Then you start swiping through Caliber's profiles, marking the ones you find intriguing.

If you are looking to meet someone with a particular background, the app also offers filters so that you can search for "investors from top firms" or "interesting founders near me." You can also search by company, position or skill, from graphic design to JavaScript.

Wondering about all the people you've looked at over time? The app keeps track of the profiles you've passed on and the ones that are of interest. For now, though, the only way to change your mind is if the profile happens to come up again on your screen, and this time you swipe right to show that you are, indeed, interested.

Available: iOS

Maybe the person you're about to meet is a loyal Stanford alumnus. Or was recently quoted in the news. Or just returned from a Caribbean vacation. If so, Refresh can dig up those details to help you find common ground when you meet someone new.

The app scours the Internet and social media to create a dossier on the person you're about to meet. It shows, for instance, the person's work history, culled from LinkedIn, and the person's most popular tweets on Twitter. Altogether, it claims to analyze data from more than a hundred sources to find relevant, conversation-starting information. Know someone in common? Graduate from the same college? The app will also highlight mutual friends and interests.

Having that information handy can help build stronger relationships, said Bhavin Shah, CEO and co-founder of the Mountain View, California-based start-up. Sync it with your email and calendar, and the app can also help you keep track of your interactions with that person so that you can pick up where you left off. No need to break the ice with an awkward comment about the weather.

Available: Android and iOS

Founded in 2002, MeetUp has since come to dominate the local networking scene, helping to organize more than 9,000 gatherings a day among its 19 million members around the globe.

If you're looking to mingle with fellow female entrepreneurs in your neighborhood or talk about your Web project with other developers, MeetUp is your best source. Its app lets you search for nearby meetings, browse groups based on your interests and RSVP for upcoming events.

Dan Fugardi, co-founder of computer software start-up Clout.com, has used it to host events connecting engineers and executives at growing companies in Southern California. It's a low-pressure way to mingle with people, he said, and chances are, you will meet someone who can help you in the future.

Available: Android and iOS

If you have a few hours of downtime, you can make the most of it with CityHour, an app that helps you find people within a 50-mile radius interested in meeting in-person in the next two hours.

Through the app, you can search for nearby people from a particular industry or with similar networking goals and request a meeting. If you're traveling and don't know the neighborhood well, the app can also suggest local venues. And if you're open to people reaching out to you, you can block off certain times in your calendar when you know you will be free.

Available: iOS (Android coming soon)

If you're heading to a business conference, Bizzabo can help make it as worthwhile as possible. The app shows you other people attending the same event and helps connect you with them, even after it is over.

Through the app, you can see other attendees' LinkedIn profiles, follow them on Twitter or send them a personal message. Not sure about who to approach in the sea of people? The app also offers suggested "leads" based on your background, and you can also filter the list by company name or position.

There are caveats. Most conferences of a certain size must pay a fee to offer the app to attendees, so it may not be available for your particular event (it will, however, show you nearby conferences using Bizzabo). It also requires attendees to sign up and join the conference community, so there's no guarantee that you will find the people you want to meet through the app. Of the more than 60,000 people expected to converge at this year's Oracle OpenWorld in San Francisco, for instance, only a tiny fraction were logged into the Bizzabo app.

Available: Android and iOS

Five years ago, Syed Shuttari would go out to lunch in downtown San Francisco and see thousands of other professionals having lunch, too, many of them eating alone.

Shuttari saw lunch as the perfect opportunity to network with other people, and so he began developing Let's Lunch in 2011. Since then, it has grown to about 30,000 active networkers using the website each month to set up lunch and coffee meetings.

Its new iOS app—expected to be launched within a few weeks—makes scheduling a face-to-face meeting even easier. It syncs with your calendar, and you designate the days and time that you're available. Just as with Tinder, you swipe through its profiles. But when you see someone you would like to meet, you drag that person's profile down to the day and time you both have available in your calendar. Now you've arranged a power lunch. The app tries to avoid back-and-forth messaging, Shuttari said, saving that conversation until the two meet in person.

Available: iOS (in about two weeks)