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After Silicon Valley, Stockholm is the second-largest producer of "unicorn" startups -- those valued at more than a billion dollars. "The region has produced companies such as Mojang, Skype, Spotify and Klarna," says Pär Hedberg, founder of incubator STING and co-working space SUP46. "That's a big change compared to ten years ago when there were no startup icons." According to research by data analytics firm BrightSun, Sweden is the largest outlier in Europe at every stage of investment -- the average series A round in Sweden, for instance, is roughly $8 million (£5m). The reason for this innovative ecosystem, says venture capitalist PJ Pärson from Swedish investment firm Northzone Ventures, dates back to the 90s, when the government introduced subsidies for personal computers. "Everyone below the age of about 35 grew up with a PC," he says. "That created a fertile ground for new business ideas."

Truecaller

Kungsgatan 15, Stockholm 111 43

Truecaller is a predictive phones book that helps you reach the right person based on your locations, time of day and call history. The app has a master list of 1.5bn phones numbers. In December 2014, it announced it had 100m registered users, mostly from emerging markets such as Latin America and India. It has raised $80m in funding from Kleiner Perkins, Atomico and Sequoia.

FishBrain

Regeringsgatan 25, 8th floor, Stockholm 111 53

Sport fishing is going digital. FishBrain is a specialised social network for anglers that crunches data to advise anglers where to fish. They can check in during a fishing trip and post photos of the bait they are using, what they are fishing for and what they catch. It also collects ambient data on air temperature, humidity, water and wind conditions. In 2014, it introduced an algorithm to forecast when and where to drop a line for nine fish species, based on the 250,000 catches and 50,000 lures users have logged. The startup, which launched an app in 2013 and has $2.6m in funding, now has 650,000 users, of which more than two-thirds are in the US, where it dominates the market.

Sinch

Fabrikörvägen 4, 6tr, Nacka Strand, Stockholm 131 27

Spun out of VoIP company Rebtel, Sinch is a communications plug-in that can be embedded into any app. Like competitors Twilio and Layer, it allows developers to integrate SMS into the app, and also offers voice calling. It launched its SDK to customers in 105 countries last December and claims four billion minutes of calls were made within six months of launch.

KnC Miner

Birger Jarlsgatan 33, 5tr, Stockholm 111 45

KnC Miner uses its powerful data centre in the Arctic Circle to verify and process Bitcoin transactions. Despite receiving lawsuits from dissatisfied customers, the firm raised $15m in a series B round led by Accel Partners, and existing investors Creandum and GP Bullhound. According to the company, it generated revenues of more than $100m in its first 18 months.

Acast

Drottninggatan 82, Stockholm 111 36

Acast brands itself as Spotify for podcasts. Its idea: to insert ads into the most relevant parts of a programme, using a drag-and-drop tool that inserts the ad at a suitable point. Funded with $5m, Acast selects ads based on listener data -- where they are located, time of day and so on. Customers include The Guardian, Sky Sports, Nature, The Sun and Coca-Cola.

Goo Technologies

Linnégatan 89E, Stockholm 115 23

Backed by Rovio founder Kaj Hed, Goowants to bring 3D animation to HTML5 and WebGL-based web pages. When it launched in 2011, Goo created instant 3D games for browsers, and has since expanded to ads. It claims to have created the first WebGL-powered online ad, which enables a user to move through a 3D scene and look at an advert from multiple angles.

Volumental

Drottning Kristinas väg 53, Stockholm 114 28

Volumentalwants to digitise the human body. Its big idea: low-cost, high-resolution software that allows you to scan body parts using a depth-sensing camera like the Kinect to create precise models that can be uploaded to a 3D printer. The startup raised $3m in 2014 from Rovio's investment firm MOOR and others, and plans to expand from medical fields into fashion footwear.

Instabridge

Regeringsgtan 29, Stockholm 111 53

Instabridge is a crowd-powered Wi-Fi network. Its app lets you share your hotspot details and gives access to other user hotspots. The company claims 1,000 networks are added each day. It took in $1m in a seed round from Creandum, GP Bullhound and a number of angels, and is growing fast in emerging markets such as Mexico, Argentina, Brazil and India.

FLIC

Teknikringen 26, Stockholm 114 28

FLIC's internet-of-things smart button sticks to any surface and can be programmed as a smart home and smartphones device controller, so you can adjust your lights or thermostat, take pictures, make phones calls or order taxis. One of Sweden's most successful Indiegogo campaigns, it raised $800,000 -- eight times its goal. The Bluetooth devices cost around $25 a unit.

Lookback.io

800 El Camino Real, Suite 180, Mountain View, CA 94040 US

Founded in Stockholm but recently relocated to Silicon Valley, Lookback.io allows UX designers to see through the eyes of their customers by analysing user experiences via high-quality video testimonials captured on mobiles devices. Funded with $2.1m by investors including Index Ventures, its customers include Spotify, King.com and Venmo.

This article was originally published by WIRED UK