U.K. mobile-first bank Monzo sent a warning shot across the bow of the financial industry in 2016 when it needed just 96 seconds to raise more than $1.2 million through crowdfunding for its prepaid card.

With the U.K.’s banking infrastructure creaking, major banks — and consumers — still grapple with the back-end processes and systems built in the 1970s.

It’s a problem for the banks, as it means they need to retain the services of the limited number of programmers fluent in the ancient COBOL programming language. But it is also bad news for consumers, as online banking delivers a user experience from the digital stone-age. Everyone wants to move on to well-designed apps that help improve their lives.

What Monzo delivered was a banking app with greater details about transactions, push notifications updating your spending, budget tools and blocking options.

Four years on and the company has come a long way: It has earned a full banking license from regulators, enabling it to offer checking accounts and tax free savings accounts In November last year, Monzo raised $108 million in Series E funding, valuing the company at more than $1.3 billion. Last month, the company surpassed 2 million users. Most recently, the company is thought to be in talks to take on an additional $100m investment – thought to be from Y Combinator’s Growth Fund, which could push the company over the $2bn mark.

This so-called “unicorn” is being hunted. As the fastest-growing bank in the U.K., it was inevitable that the more-traditional banks would use Monzo as a template for modernizing their approach. For example, Halifax, which is a subsidiary of Bank of Scotland, one of Britain’s big three banks, announced plans for an app that was so close to Monzo that CEO Tom Blomfeld called it out on Twitter. Monzo is also facing stiff competition from other challenger banks that offer similar functionality, such as Revolut, Starling and N26.

Monzo also must contend with an $800 billion gorilla in the room. Earlier this year, Apple surprised the tech world by announcing that this summer it would launch an Apple Credit Card.

As Apple’s Jennifer Bailey ran through the features of the card in the March keynote event, listeners could be forgiven for thinking that some were strangely familiar. The Apple Card is reported to mimic several of Monzo’s innovations, such as extra detailed statements and charts showcasing spending. Clearly, Monzo is doing something right.

Good Design
What really marks Monzo out is the focus on product design. For example, when the app opens up and displays recent transactions you don’t see abbreviations and transaction codes that the industry loves. Instead, Monzo uses predictive algorithms to fill in the actual names of the retailers you used — complete with profile icons and even a map showing where each transaction took place.

The app also makes use of push notifications: When you spend money, within seconds a notification on your phone will arrive, acknowledging the transaction in the app — and also updating you on how much money you have spent on that given day.

Sending and receiving money is also easier: Money can be transferred either directly to other Monzo users in your contacts as easily as sending a text message, or weblinks can be generated to send to friends who don’t use Monzo.

Useful functionality, however, is already being emulated by Monzo’s bigger rivals. A “card freeze” feature that deactivates a card without funny cancelling it has now been copied by several larger banks, which shows the challenge Monzo has to keep its edge.

Good Behavior
One of the core features of the app isn’t just to make spending money easier, but also to help customers budget and save. Transactions can be categorized by type (household, travel, etc.), and regular payments can be flagged by the user. Then Monzo does its best to predict your spending for the month, and will warn you if it looks like you are living beyond your means. One particularly nifty feature is that you can set Monzo to round up to the nearest pound – and add the extra pennies from each transaction into a separate savings pot to force you to save.

You can also choose to ban any transactions with gambling companies, just in case you tend to get careless.

The company also wants to help the “unbanked,” such as homeless people and refugees, who typically find it difficult to get a bank account because of a lack of documentation or permanent residence.

“Whether you’re an elderly person living in the countryside, someone struggling with mental health issues or you’ve been made homeless, having a bank account you can manage is an essential part of everyday life,” the company explained its ethos to the Financial Times.

For these users, it offered a basic account can be opened with just a biometric residence permit instead of a full passport. The intention in the future is to lower the requirements further and enable people who have submitted an asylum application to open an account, even if the application has not yet been approved.

Monzo recently launched “Monzo Plus,” monthly subscription service that offers discounts on other financial and non-financial services, such as travel insurance, invites to events and “swag.” The aim of the service, which costs about $8 a month, is to help distinguish it from rivals.

The challenge for Monzo now, other than growth, will be reaching out to consumer segments beyond the young and tech-savvy. Banking is an industry that notoriously takes advantage of consumer inertia as customers stick with the same bank for often their entire lives, so Monzo will not just have to persuade people to switch, but to take on that risk with a less established name.