10. Truecaller can be used to figure out who's calling you.
What it is: Truecaller is an app that helps users to screen and block unwanted calls. The platform has a global directory of millions of numbers, so there's a good chance it can identify who's calling — like your bank or a telemarketer — even if that number isn't stored in your phonebook.
You can also search for phone numbers on Truecaller's platform and see the top reported spam numbers in your area.
The company raised $60 million (£39 million) in 2014 from investors including Atomico and Kleiner Perkins Caufield & Byers.
Total amount raised: $80.1 million (£52.1 million)
Headcount: 148
9. SoundCloud is a popular music streaming site.
What it is: Europe loves its streaming sites and SoundCloud is in the forefront of that. Started in Sweden in 2007, SoundCloud has become the go-to place for DJs and musicians to share their latest music. SoundCloud has moved its head office to Berlin and currently has over 400 employees. It has embarked upon an ambitious plan to monetise, introducing premium accounts and deals with major record labels.
There were reports in May that Twitter and SoundCloud were in talks about a possible acquisition to create a music feature on Twitter, but it doesn't look like those conversations ever amounted to anything.
Total amount raised: $123.3 million (£80.3 million)
Headcount: 478
8. The Pirate Bay is a well-known file-sharing site.
What it is: The Pirate Bay, founded in 2003 by a group of Swedish men who believed content should be free, has become one of the world's most well-known illegal filesharing websites.
Though the site was shut down for several months earlier this year for copyright infringement, we considered it on this list because it has changed the way people consume media.
Users can browse the site to find pirated movies, music, TV shows, and books, and then find torrent links to download the files. The site earns money through advertising on its pages.
The site is now run by new, anonymous owners that are not connected with The Pirate Bay's original creators.
Total amount raised: Unknown
Headcount: Unknown
7. EA Digital Illusions CE is making the new "Star Wars" video game.
What it is: EA Digital Illusions CE, commonly known as "DICE," is owned by global video game giant Electronic Arts. DICE is behind the "Battlefield" series of games and is currently working on a sequel to "Mirror's Edge," the futuristic parkour game that it released in 2008.
Another key game that the company is working on is "Star Wars Battlefront," which is scheduled to be released on November 17. EA predicts that it will sell between 9 and 10 million copies of the game.
Total amount raised: Unknown
Headcount: 550
6. Tictail helps independent businesses sell their products? online.
What it is: Tictail helps small companies sell their items online. Customers can shop using Tictail's website and mobile app to find products from independent brands that wouldn't have otherwise had an online presence.
Tictail raised $22 million (£14.3 million) in July from investors including Creandum, Thrive Capital, Balderton Capital, and Acton Capital.
Total amount raised: $32.6 million (£21.2 million)
Headcount: 64
5. iZettle is a mobile app that lets businesses take card payments.
What it is: iZettle produces a mobile app and card reader that allows businesses to accept payments on their phone and tablet, just like Square does in the US. iZettle is different than Square, however, because it supports chip and pin technology, an extra security measure that requires cardholders to enter a PIN number and that hasn't been widely rolled out in the US yet.
iZettle has bought in investment from some well-respected VC firms. Its most recent round of funding came in May 2014 and saw it raise $55.5 million (£36.1 million).
Total amount raised: $175.8 million (£114.5 million)
Headcount: 234
4. Mojang is a the $2.5 billion video game company
What it is: Mojang is the Swedish game development studio that's famous for its one smash hit game: "Minecraft." Started by Markus "Notch" Persson in 2010, Mojang oversaw the development of "Minecraft."
The easy-to-play block-building and adventure game was an instant hit, especially with children. Mojang was eventually sold to Microsoft for $2.5 billion (£1.6 billion) in September 2014. All three cofounders left the company, and Persson is now living in a $70 million (£45.6 million) luxury mansion in Beverly Hills which he bought after outbidding Jay Z and Beyoncé.
Total amount raised: Unknown
Headcount: 127
3. King is the the maker of "Candy Crush."
What it is: Swedish company King is the digital studio behind some of the world's biggest casual video games. Chances are you're aware of "Candy Crush," King's biggest hit. But the company isn't stopping with just one hit game. It has a vast portfolio of apps and games - and it isn't showing the growing pains that plagued Zynga, the other well-known casual games giant.
CEO Riccardo Zacconi has been in charge of King since starting the company back in 2003. He's seen King grow from a small startup to an international games giant. King's March 2014 IPO saw stock fall initially, but it's been performing well since. The company booked $2.3 billion (£1.4 billion) in 2014 revenue.
Total amount raised: $43 million (£28.1 million) - but it went public in 2014
Headcount: 2,573
2. Spotify is Europe's biggest music streaming service.
What it is: Spotify, the world's biggest streaming site according to the number of users, has its head office in Stockholm. The streaming service was started by Daniel Ek in 2006, and now has 60 million users around the world (15 million of those are paying subscribers).
Spotify has been touted as a possible candidate for an IPO in 2015 - although it looks like it's instead focused on raising money. It was reported in January that Spotify is raising $500 million (£325.8 million) at a valuation that could top $6 billion (£3.9 billion).
Total amount raised: $1.1 billion (£716.5 million)
Headcount: 1.958
1. Klarna lets customers buy items online with just one click.
What it is: Klarna, valued at over $1 billion (£650 million), is a payment platform that makes online checkouts very simple for customers.
To pay for an item, customers just drop an item into their online shopping cart, click the pay button, and then enter their email address and postcode. That's far easier than using PayPal, Klarna means that you don't have to remember a password.
Klarna is huge in Sweden — 30% of all online purchases in the country take place through its service. Last year it processed $9 billion (£5.74 billion) worth of transactions globally.
Total amount raised: $282.1 million (£183.7 million)
Headcount: 949