Less than a decade ago, the patch of land in Belfast harbour formerly known as Queen's Island was a wasteland. The shipyards that built the Titanic had fallen into decline. Today, rebranded the Titanic Quarter, it is the focus of a £7bn regeneration project that has yielded a Titanic-themed visitor centre, a college campus and one of Europe's largest film studios.

The island is also home to a new generation of tech innovators. At the Northern Ireland Science Park, more than 110 companies, from software developers to aerospace engineers, are working to re-establish Belfast as a centre of scientific and technological excellence.

According to a recent report, Northern Ireland's knowledge economy is growing nearly three times faster than the rest of the UK. A few years ago, Belfast had no recognisable startup scene, but the tech community has passionate advocates in groups such as Digital Circle (see below) and the University of Ulster's Office of Innovation. Belfast now has meet-ups and coding groups, hackerspaces (such asthe excellent Farset Labs) and a credible angel investor network, Halo, based in the science park. It seems that graduates pouring out of Queens and the University of Ulster are finding new incentives to stick around. "Belfast is good for young people," says Mary McKenna, CEO of Learning Pool and current chair of Digital Circle. "It has a lively social scene, costs are lower, there's space, it's well connected. If I were starting a tech business today, I'd start it here."

AIRPOS

Martin Neill co-founder and CEO

Founded 2009 Headcount seven

What is it? Software for independent retailers.

How did it come about? Running a Belfast web design company, Neill noticed "small retailers were finding it difficult to sell online". With developer Kieran Graham, he set up a company to address the issue when "the notion of a tech startup in Northern Ireland didn't really exist".

How does it work? The company was an early developer of cloud ePOS (Electronic Point of Sale) software, letting retailers accept payments on a variety of internet-connected devices, including tablets. The product also includes software for inventory control and a webstore – "so if there's less footfall in the high street, you can continue to trade online".

How are they doing? "We've licensed the technology to Just Eat, the world's largest takeaway portal, and teamed up with PayPal on their in-store payment technology, PayPal Here."

Why Belfast? "I'm passionate about it. A new generation has grown up, post-conflict, and we must give them something if we want them to stay."

SISAF

Suzanne Saffie-Siebert founder and CEO

Founded 2008 Headcount three

What is it? A biotech company attempting to make drug delivery "smarter".

How did it come about? When her TV producer husband was moved to Northern Ireland by the BBC five years ago, Saffie-Siebert, an expert in pharmaceuticals and drug delivery, decided to establish her nascent company in Belfast.

How does it work? "We don't believe you need another drug to cure diseases like cancer, diabetes or skin disorders. Available drugs are good enough – the problem is that they're not smart enough." Using nanosilicon as a carrier, SiSaf's delivery system allows drugs to target affected areas very precisely, making it safer while enhancing the efficacy of a drug.

How are they doing? The morning we met, Saffie-Siebert had just found that her system had passed phase one of its clinical trial – "meaning we are now formally safe to use for any application". The company's first focus is acne: "Not a life-threatening disease, but a huge issue among teenagers, who take a lot of damaging antibiotics and steroids to treat it. We can make the drug go deeper into the skin and clean out the bacteria without creating any nasty antibiotic resistance or other side effects."

INLIFESIZE

Greg Maguire co-founder and CEO

Founded 2011 Headcount six

What is it? A games company developing mobile apps and a digital comic platform.

How did it come about? Four years ago, Maguire, an animator and visual effects expert who worked on Harry Potter 3 and Avatar, returned from the US to set up an animation programme at the University of Ulster. In 2011, he founded Inlifesize with games veteran Phil Campbell.

How are they doing? Last year, they released their first app, Fairy Magic, which allows users to interact with fairies against a real-world backdrop. The company has also developed a digital comic platform called Deep Paper: the first publication to use the technology, 13 Coins, features interactive 3D covers and artwork by illustrator Simon Bisley.

Why Belfast? "It feels like the community is thriving. It's a good pond to play in."

BREWBOT

Chris McClelland founder and CEO

Launched 2013 Headcount five

What is it? A robot that brews beer.

How does it work? The brewer connects to the machine via the Brewbot mobile app, chooses or creates a recipe, starts the machine and adds the ingredients when prompted. "It's the perfect controlled environment for making beer, but we didn't want it to be completely automatic," says McClelland, head of product-design company Cargo. "So it's not like a breadmaker of beer.If you make changes, Brewbot will remember."

How are they doing? "We travelled to Portland, Oregon to launch it on Kickstarter in September and took Brewbot on an 11,000-mile journey around America. In San Francisco, we were invited into places like Twitter and Square." They sold 52 Brewbots during the trip – you can pre-order one at www.brewbot.io for £1,700 – and exceeded their target on Kickstarter, raising £114,368.

JAR TECHNOLOGIES

James Hunter founder and technical director, and Heidi Nicolls business development manager

Founded 2011 Headcount six

What is it? JAR provides products for the application performance testing market.

What does that mean? "Basically, these products make sure software and applications work when they're deployed to the customer," says Hunter, a software engineer by training. "A lot of applications are developed in very sterile R&D environments. We guarantee that their software will work in the real world."

How are they doing? "We're 100% export," says Nicolls, who joined the company four months in. "We don't service the UK market at all. The application performance market is picking up speed in China, India, Brazil, Japan: those countries are where we've been most successful."

Why Belfast? "There's a real buzz and we feel the support is here for us if we need it," says Nicolls.

WOMEN WHO CODE BELFAST

Sheree Atcheson founder

Founded 2013 Members 91

What is it? New branch of the women coders meet-up group.

How did it come about? A conversation with the founder of Women Who Code, an international organisation with roots in San Francisco, convinced22-year-old Atcheson, a computer science graduate from Queen's University, to set up her own branch in Belfast. "I thought their aims, which are to eradicate the gender bias in IT, were very relevant to Northern Ireland."

How is it doing? "I founded it 30 days ago and we've just had our first packed-out event," Atcheson said late last year. "Our second event is now packed out too and events have been organised until June."

APPCAMP

Tom Gray founder

Founded 2011

What is it? Two-week summer courses in app development for university students.

How did it come about? "Northern Ireland is our heartland," says Gray, chief technology officer at Belfast software company Kainos. "We're here for the long haul, so anything we can do to improve the quality and volume of people coming into the IT profession helps us in the long term." Gray organised the first AppCamp in Belfast in summer 2011; last year, the event also took place in London.

How does it work? "We give students training on how to develop an iPhone app. At the end, we bring in a panel from across the industry and the students pitch their apps. The best executors get eight weeks of working with pro developers at Kainos and access to our marketing and UX teams, to deliver the app."

How's the games industry in Belfast? "It's very embryonic, but the level of technical capability is very high. There are some exceptionally good developers here."

TAGGLED

Ian Scott founder and CEO, and Catherine Morris community manager

Founded 2013 Headcount five

What is it? A video tagging platform with a focus on fashion.

How did it come about? A year ago, Scott heard a friend complaining that he'd seen a jacket he liked on TV and had spent hours trying to find it on Google. The search was fruitless but it gave Scott, who was running a business software company in Belfast, the inspiration to start Taggled.

How does it work? "Video bloggers or brands coming to our platform can tag the content very easily through drag-and-drop," says Morris, who joined the company soon after it started. "Then, whether on a blog or social network, they can access the info by clicking on the tag. If the viewer clicks through to a retail site and buys the product, we get a commission from the retailer and share the profit with the blogger."

GOPREZZO

Aaron Taylor founder and CEO

Founded 2011 Headcount nine

What is it? A tournament platform that lets gamers compete for real-world prizes.

How does it work? "We connect brands to gamers through their favourite games," says Taylor. The platform allows gamers to compete for brand-sponsored prizes. What's unique, says Taylor, is "we can take scores from any game and put them on the same leaderboard. We have an algorithm to normalise those scores."

How are they doing? They have raised £850,000 over three funding rounds, says Taylor, and opened an office in New York. Last year, it won a place in San Francisco's RocketSpace, one of the top accelerators in the US.

SOLACATCHER

Mervyn Smith co-founder and chief technical director

Founded 2013 Headcount two

What is it? A low-cost solar water-heating system.

How does it work? "In essence, it's a black tank on the side of your house," says Smith, a reader in solar-thermal energy at the University of Ulster. "It collects solar radiation during the day and transfers the thermal energy into heat, which is stored inside the vessel until you need hot water. What's novel is the diode heat transfer mechanism, which facilitates optimal collection and heat retention."

How did it come about? "I developed the concept through my research. We patented the technology and spun out the company (SolaForm) around the product. It only came into existence last July, so it's very early days." Smith and his co-founder Dominic McLarnon see SolaCatcher as a low-cost alternative to other solar-water systems. "We're teaming up with a local housing authority in April and putting a number of these units on properties in Londonderry and Belfast," says Smith.

MOF TECHNOLOGIES

Stuart James co-founder and chief technical officer

Founded 2012 Headcount three

What is it? A company developing porous nano-materials for applications in clean energy and other areas.

How does it work? Metal-organic frameworks (MOFs) are crystalline materials composed of metal ions and organic molecules known as linkers. They act as molecular sponges and, due to their extremely high surface area, are very good at storing gases such as methane and hydrogen.

Where are they? "We've been in a research phase for last year," says James. "Now we're moving into a commercial phase." Applications include carbon capture and natural gas storage, but the technology has more potential uses than James and his colleagues are able to envisage. "We get into conversations with a company and they will suggest something to us that we haven't thought of: trapping of odours; air conditioning. There are all kinds of possibilities."

DISPLAYNOTE

Lisa McIlhone marketing and partner support specialist

Founded 2012 Headcount 22

What is it? Screen-sharing software for computers and mobile devices.

How did it come about? Co-founders Paul Brown and Andrew Bell have backgrounds in education technology. "They saw a need for software to embrace the rising use of tablets in education," says McIlhone.

How does it work? The software lets the user share their computer screen with any number of devices, including mobiles and tablets (which access via a free DisplayNote app). It allows teachers to share lessons or any content from their computers – YouTube videos, PowerPoint presentations – and students can take screen captures or make notes on the app."

Future plans "It was designed with schools in mind," says McIlhone, "but we are getting ready to launch cloud functionality, which means you can share screens in different locations, so that will push it further into the corporate sector."

SIXTEEN SOUTH

Colin Williams founder and creative director

Founded 2008 Headcount nine core staff and 76 on contract.

What is it? Animation studio making innovative children's TV programmes.

How did it come about? After a successfulcareer producing commercials, Williams returned to his roots in design and animation and make children's programmes. His company's first show was Sesame Tree for the BBC. "I'd never made a full-length TV show before and to think we'd ever win the gig was absurd, but we did.. It gave us national exposure." The company went on to make the hit show Pajanimals in partnership with the Jim Henson Company.

How are they doing? One of the UK'S 10 fastest-growing tech startups , the company has grown 2,214% since 2008. "We've pre-sold our fifth show, Driftwood Bay, to 20 countries and we're aiming for 100. We've created a hybrid animation technique for the show, a cross between stop-frame and 2D design."

Why Belfast? "It feels like a city that is healing and going through a transformational process. That brings its own energy. People have been so resilient for so long time, it's made them strong."

DIGITAL CIRCLE

Matt Johnston founder

Founded 2008 Headcount Current membership is 2,154, covering 322 businesses across the province.

What is it? An organisation to support and promote digital industries in Northern Ireland.

How did it come about? A biologist by training, Johnston started a series of tech companies in Northern Ireland before establishing Digital Circle in 2008 to "put a shape on to the local industry". He has since gone on to start a games company, Conquest Dynamics.

How does it work? The organisation, led by a steering group of local figures, provides guidance to startups on funding, investment, export and business.