Fintech – or financial technology – was a buzzword in 2015 with start-ups raising large sums of money and talking up the "disruption" they could cause the established players from banks to payment firms.
Last year, financing for fintech start-ups hit over $20 billion, a 66 percent increase on the $12 billion recorded in 2014, according to KPMG.
And new technologies could see up to 30 percent of jobs eliminated from the banking industry, Citigroup said in a study published last week, highlighting the threat to traditional companies.
So who are the hottest entrepreneurs and companies? Independent organization FinTech 50 has put together a list of the top 10 European start-ups "transforming financial services". A panel of 30 industry experts which includes the U.K. government's special envoy for fintech, Eileen Burbidge, and UBS CIO Oliver Bussmann, picked the companies that they saw as "game-changers".
In no particular order CNBC runs you through the fintech start-ups to watch.
Adyen is an international payments processing company that counts Uber, Spotify and Facebook among its clients.
The Dutch firm was founded in 2006 and offers payment services on desktop, mobile and in-store.
Payments is an increasingly crowded sector with competitors including Stripe and Braintree.
Adyen has some high-profile backers. Last year, it raised an undisclosed amount of money from wealth management fund called Iconiq, which courts Facebook boss Mark Zuckerberg among its clients. It is a so-called "unicorn," being valued at $2.3 billion.
TransferWise is a peer-to-peer money transfer service described by the FinTech 50 panel as one of the "original fintech revolutionaries".
The London-based firm allows users to transfer money across different borders and currencies at lower costs than traditional banks.
Last year, TransferWise raised $58 million led by U.S. venture capital firm Andreessen Horowitz in a round that valued the start-up at $1 billion.
Nutmeg was chosen on the list "for taking investments online".
The British start-up is an online wealth manager which is regulated by the U.K.'s Financial Conduct Authority (FCA).
Nutmeg recently cut its prices as a number of competitors entered the market and said it would soon introduce an automated investment advice service or "robo-advisor."
Currency Cloud is another start-up in the payments space.
The British firm provides cross-border money transfers for businesses. It sets itself up as a rival to banks that usually carry out this transaction, but says it is cheaper and faster than traditional players.
Founded in 2012, Currency Cloud now processes $15 billion a year and has over 125 customers.
The start-up raised $18 million last year from Sapphire Ventures and Japanese e-commerce giant Rakuten.
iZettle is a payments processing company that provides companies with a free card reader which plugs into tablets or phones, allowing businesses to run from mobile devices.
It's similar to U.S. firm Square which was founded by current Twitter chief executive Jack Dorsey.
However, iZettle chief executive recently said that the company is different to Square as it operates in separate regions.
"We're very European-focused we are in totally different markets compared to Square...we are quite a different company," CEO Jacob de Geer told CNBC in a TV interview last year.
Last August the Swedish start-up raised 60 million euros and is backed by companies such as MasterCard and Santander.
To broaden its revenue streams, iZettle has launched a small business loan platform iZettle Advance.
WorldRemit is the start-up trying to take on the $600 billion remittances market and challenge players such as Western Union.
The British company allows users to send money via an app to people around the world to bank accounts or so-called mobile wallets for a low price. Currently, this process can take several days and cost a lot.
WorldRemit recently raised $45 million to fuel expansion into a potentially huge market. International migrants will send $601 billion to their families in other countries this year, with developing countries receiving $441 billion of that, according to the World Bank. WorldRemit is trying to become the dominant player in that market.
"Two billion people are under-banked in the emerging economies and they are our customers," Ismail Ahmed, founder and CEO of WorldRemit, told CNBC in an interview in February.
"When we send money today to different countries often the recipient has to travel long distances to go to a location where they can get cash. Mobile money services are making it so anybody who has a basic feature phone can set up an account and the mobile number becomes the account number."
There's been a whole host of new investment platforms popping up to challenge traditional brokers and eToro is one of those – but with a twist.
The start-up bills itself as a "social trading network", allowing users to copy trading strategies of other traders which they deem successful.
Investors can trade currencies, commodities, indices and contract for difference (CFD) stocks online.
Funding Circle is one of many peer-to-peer lenders that have popped up in recent years.
The company matches investors to small and medium-sized businesses and, as of December, had lent £1 billion ($1.4 billion) to firms in the U.K.
"We're committed to creating opportunities for small businesses that didn't exist before," James Meekings, U.K. Managing Director and co-founder, commented:
"For too long, they were reliant on a single line of credit from traditional providers. We're building the infrastructure where any investor, big or small, can lend."
Funding Circle has over 48,000 investors on board including the Government-backed British Business Bank.
Klarna is a payment-processing firm that's mounting a direct challenge to PayPal.
Its mission is "simplifying payments" according to its website and the approach differs to competitors. Klarna users don't need to register and can place an order by simply entering their email and zip code. Once the product arrives, users can choose when they want to pay within a 14 day period.
Last year, the Swedish start-up snagged a $2.25 billion valuation after venture-capital firm Northzone, Wellington Management and Wellcome Trust bought $80 million worth of stock from company insiders.
Zopa was one of the early peer-to-peer lenders to appear after it was founded in 2004.
The British firm is a rival to Funding Circle and to date has lent £1.3 billion ($1.8 billion).
Peer-to-peer lenders work by letting people invest their money into businesses, positioning themselves as challengers to traditional banks.
Zopa recorded a jump in revenues from £5.4 million in 2013 to £11.5 million in 2014, according to its latest set of financial results.