Germany’s thriving startup scene is one of the most unique in Europe.
The capital Berlin is home to a mixture of hackers, privacy experts, scientists, and video companies that are making waves in the tech scene.
Here are some underground companies as well as more established names that are worth watching.
Foundd is a site that recommends movies based on what you like, as well as what your group of friends likes. That's different to services like Netflix, which just look at your own viewing history.
The company earns money when people click through to buy movies on iTunes -- so it want to make the recommendations as good as possible.
Mashable reports that Foundd raised a $US350,000 (£223,000 round) of funding in 2013 from investors including JMES Investments, Lars Dittrich, and Tao Tao (a cofounder of GetYourGuide).
Plinga is a Berlin-based video game developer that creates social games for a wide audience. Founded in 2009, the company has launched a series of games, including Family Barn (27 million players) and Dragons of Atlantis (13 million players).
Unlike its competitors, Plinga makes it games available to embed around the web, so they're not just playable on its own sites. That's different to how rivals like Zynga and King work.
Plinga began as a direct competitor to Zynga, featuring a game called FunCards ('Like UNO, just better!'). It received investment from Rocket Internet, the investment firm run by German entrepreneurs the Samwer brothers.
Onefootball is a mobile app that brings together news, polls, scores, and rumours about football all in one place. Football fans tend to eat up any information about the sport, and sure enough, the company has seen over 20 million users sign up to the platform.
Since starting in 2008, Onefootball has brought in over $US20 million (£12.76 million) in funding from investors such as Earlybird Venture Capital, and Union Square Ventures.
Wooga is a Berlin video game development company that makes games for smartphones. Just like King (developer of the Candy Crush series), Wooga has found a giant audience for its games -- the company says that over 200 million people have played Diamond Dash, one of its apps.
Wooga hasn't just stopped at one hit game, though. It has also launched an Apple Watch game as well as Agent Alice, its next big smartphone app. CEO Jens Begemann said that over 80 developers worked on the game for 18 months.
Do you find it tricky to manage encryption of your emails, data, and passwords? Nitrokey is a USB stick that takes care of all that for you. The Berlin-based company has developed a physical device that keeps your data safe.
More expensive versions of the Nitrokey let you store encrypted data on the device, with the storage beta model letting users keep up to 32GB of files encrypted on the device.
The Nitrokey has been around for a while, and has seen several different versions of the product since it started life as the Crypto Stick in 2008.
There's nothing worse than ending up with an inexperienced tour guide on a city break. Thankfully, GetYourGuide lets people book tours and guides through its site, allowing travellers to find unique experiences around the world that they wouldn't otherwise have seen.
The company was started in Zürich, Switzerland, in 2008, but moved its main office to Berlin. GetYourGuide has brought in $US45.5 million (£29 million) in funding since it started, most recently a $US25 million (£15.9 million) Series B round in 2014 used to fund international expansion.
Eyeo is the Cologne-based company behind the popular AdBlock Plus browser extension which hides ads around the web. Initially released in 2006, the German company has gone on to develop a browser designed to unclutter web pages by stripping out adverts.
The company says that its desktop browser extension has been downloaded over 400 million times, and it is thought to have around 50 million active users. It also has a whitelist of ads which it considers acceptable, and only a handful of companies pay to get on the coveted list.
It's no secret that running a startup is an incredibly competitive way of life. Everyone wants to know what everyone else is doing, and tools like RivalFox make that easier. It monitors social media, online ads, and SEO among other changes to understand what competitors are doing, and then turns that data into reports.
RivalFox's founders came up for the idea for the company in 2013 after previously running a hotel booking startup. They didn't keep track of their competitors, and missed the launch of HotelTonight.
Clue is an app that helps women keep track of their period cycle. Clue alerts users when their next period is coming and also allows women to plug in information about their mood, pain, and sexual activity. You can even ask Clue health questions, like whether your cycle is normal.
6WunderKinder is the German app development company behind Wunderlist, one of the best-known To-do list apps in the App Store. Apple is a big fan of Wunderlist, naming its Mac app 'App of the year 2013.' And the service has also built up a giant user base, numbering over 10 million users by the end of 2014.
An Apple Watch app for Wunderlist launched in April, and Apple featured it in the App Store.
ResearchGate is a social network for scientists and researchers that lets them share and discuss their findings. Scientists can upload their research and measure how popular it is among their peers, giving them an insight into which studies are most useful and interesting.
The company actually started in Boston in 2008, but quickly moved its office to Berlin. ResearchGate raised $US35 million (£22.3 million) from investors in 2013, including Microsoft cofounder Bill Gates, Tenaya Capital, Dragoneer Investment Group, and Thrive Capital.
Blacklane is Germany's answer to Uber, and has expanded fast since its launch in 2011, raising over $US22 million (£14 million) in funding. By 2013, the company had expanded outside of Germany to Austria, Switzerland, the Netherlands, Italy, France, and the UK. Now, the company is operating in North America and over 50 countries worldwide.
There are some major differences between Blacklane and Uber, though. On Blacklane, you can book rides in advance if you know you're going somewhere in the future, and you can also call the company up to order a car.
Blacklane CEO Dr. Jens Wohltorf said in an interview with Tech.eu that the company now serves 185 cities and 300 airports, more than Uber, its biggest competitor. International expansion has been Blacklane's biggest priority -- it even ended its Smart car service in Berlin so that it could focus on expansion instead.
Started in 2011, Delivery Hero is an online meal delivery service that operates in 34 countries around the world. It lets customers order food from restaurants, and handles the payment and delivery. The company has over 1,500 employees around the world with over 100,000 participating restaurants.
One method that Delivery Hero uses to expand overseas is acquiring local food delivery companies. It acquired UK-based delivery startup Hungryhouse in 2013 and acquired Turkish delivery company Yemeksepeti for $US589 million (£375.7 million) in May.
EyeEm is a Berlin-based photo-sharing app that started in 2010 when CEO Florian Meissner lost his camera in New York. He turned to his iPhone instead, and discovered photo-sharing communities online. EyeEm is different to Instagram because in addition to uploading and sharing photos, users can sell their photos through the app.
There were rumours in 2014 that EyeEm was in talks with Yahoo about an acquisition. But if there was a deal, it never came through.
SoundCloud is one of Europe's best-known music companies. It lets musicians and DJs upload their music and remixes, and fans can listen to tracks and follow record labels and individuals. Just like Spotify and Tidal, SoundCloud is positioning itself as a major player in the upcoming streaming war between Apple and European tech startups.
There was speculation in May 2014 that Twitter was in talks to acquire SoundCloud to bring music to its service. But no deal was struck between the two companies, and the purported $US1 billion (£638 million) acquisition was called off. Rumour has it that the deal fell through because of concerns over music copyright issues on the platform.