Curve, the London-based “over-the-top banking platform,” has raised $55 million in new funding. The startup lets you consolidate all of your bank cards into a single Curve card and app to make it easier to manage your spending and access other benefits.

Curve’s Series B round is led by Gauss Ventures, the London-HQ’d fintech investor, alongside Creditease, IDC Ventures and previous backer Outward VC (formerly Investec’s INVC fund). A number of other early investors, including Santander InnoVentures, Breega, Seedcamp and Speedinvest also followed on.

The new round of funding values Curve at $250 million (or one-quarter unicorn, so to speak), and will be used by the company to continue adding more features to its platform and for further European expansion. (It also plans to launch in the U.S. in 2020). To date, the company claims 500,000 users and says it is on track to reach 1 million by the end of the year.

Curve is currently available in 31 countries across Europe, with around 30% of its customer base coming from outside the U.K. “We [have] identified a few countries where the organic pull is fantastic, and we are about to double down on them,” Curve founder and CEO Shachar Bialick tells me.

Like a plethora of fintech startups, Curve is building a platform that essentially turns your mobile phone into a financial control centre that re-bundles disparate financial products or functionality to offer a single app to help you manage “all things money.”

However, rather than building a new current account — as is the case with the challenger banks such as Monzo, Starling and Revolut — Curve’s “attack vector” is a card and app that lets you connect all of your other debit and credit cards (sans Amex) so you only ever have to carry a single card.

Once you’ve added your cards to Curve, you use the app to switch which underlying debit or credit cards you wish the Curve Mastercard to spend from, and can track and see a single and consolidated view of your spending regardless of which card was charged (and therefore which of your bank accounts the money was pulled from).

In other words, Curve isn’t asking to replace your existing bank accounts but is pitched as a cloud-based platform that runs “over-the-top” of existing banking and payments infrastructure. Historically, the over-the-top terminology has been used to describe the way video streaming services such as Netflix run “over-the-top” of existing broadband infrastructure.

“For Curve to succeed in its mission of bringing banking to the cloud, we need [to continue] to build the product; tiny experiences that together create a whole new offering,” Bialick continues. “Our money is everywhere and the job of connecting it all together to one seamless experience requires many resources, and especially many talented people. The latest Series B will enable Curve to re-bundle more of your money: experiences such as Curve Send (peer-to-peer payments), and Curve Credit (post transaction installments for any payment, anywhere).”

Alongside Curve’s all-your-cards-in-one functionality, the Curve app lets you lock your Curve card at a touch of a button, provides instant spend notifications, “zero FX fees” when spending abroad or in a foreign currency and the ability to switch payment sources retroactively. The latter is dubbed “Go Back in Time” and means if you make a purchase via Curve that gets charged to a card other than the one you intended, you have two weeks to change your mind.

More recently, Curve has re-vamped its cashback feature in a bid to draw in more customers for the premium versions of the Curve card. With the new Curve Cash programme, customers get 1% instant cash back on top of any existing rewards cards that they have plugged into the app, potentially earning customers double rewards on purchases. You simply pick from the list of retailers supported for cashback — you are allowed to choose between three and six retailers, depending on which Curve plan you are on — and then get 1% cashback for any purchases made at those stores.

Bialick claims that Curve’s over-the-top model is also producing higher engagement than many challenger banks, with customers spending on average £1,500 per month through the Curve platform. (As an imperfect reference point, challenger bank Monzo says that around 30% of its users top up their account by £1,000 or more per month). I’m also told that 15% of Curve’s users have added a challenger bank card to their Curve account, which also makes for an intriguing and even more nuanced comparison.

And whilst Curve is arguably trying to define a new market category — at least here in the West — and therefore isn’t the easiest of products to explain, Bialick says that existing Curve customers are the startup’s biggest advocates.

“There isn’t just one thing that pulls customers to Curve, there are as many pulls as [there are] the number of ‘money jobs’ one has. All your cards in one, fee-free spending abroad, ‘Go Back In Time,’ to name a few, all attract and retain our customer base. Indeed, awareness and brand building is key, especially amongst all the noise, but that’s where our customers are proving invaluable, telling their friends about Curve, which drives most of our adoption with 2,000 plus new accounts per day.”

To win in this new category of banking, Bialick says the company needs to steadfastly stick to its mission to reduce the number of steps it takes to carry out everyday money-related tasks. “The winners will be the companies… [that] create the most seamless experience, removing as much friction between the customer and their money.”