How Monzo built a bank of the future on AWS
Monzo is a digital challenger bank famed for its convenience, distinctive coral-coloured debit cards, and innovative services to help people and businesses manage their money.
Examples include an automatic saving option that rounds up purchases to the nearest pound and places the difference in a savings pot, and the option to get salary payments advanced by a day without cost. You can also freeze and unfreeze lost cards within the app.
Today Monzo has more than four million current account customers, with that number growing all the time, and it has operated on the AWS cloud from day one.Chris Evans, Technical Director for Platform and Reliability at Monzo, explains: “AWS has helped Monzo to operate reliably and scale rapidly, providing the secure infrastructure needed for this new form of online banking.”
Online banking revolution
Monzo’s growth in the UK has been rapid, accelerating from a start-up with around 300,000 users to a household name with millions of customers in just a few years.
Recalling the early days of online banking, before challengers like Monzo emerged, Chris says: “Many of us will remember how online banking had a poor user experience, there were security concerns, and it wasn’t always compatible across different devices.”
Monzo saw an opportunity to redefine how customers interact with financial institutions in the digital age.
We’re on a mission to be one of the top banks in the UK. We’re solidifying and growing our position every day.
“As consumers we expect transactions to be instant, and secure. We want information to be immediately accessible, we want a friendly interface, and we want functionality like push notifications and digital receipts,” he says.
“Monzo can provide all that and more. But we also have the core platform, people and skills to further disrupt the industry in the near future. We’re on a mission to be one of the top banks in the UK. We’re solidifying and growing our position every day.”
Working with AWS
Chris cites two key reasons why AWS was the natural choice for Monzo from the start. Firstly, AWS met regulatory requirements for banks using off-premises cloud services and backed this up with a strong reputation. As Tom Blomfield, Monzo’s co-founder and President, noted: “AWS differentiates itself as a forward-thinking cloud vendor that understands enterprise concerns and works with regulators and customers to launch new features.”
One of these was AWS CloudTrail, a service that enables governance, compliance, operational auditing, and risk auditing across your AWS accounts.
“CloudTrail is fundamental to our security and activity within the cloud,” Chris explains. “It automatically provides us with an ‘event history’ of activity in our AWS accounts, simplifying security analysis and enabling us to troubleshoot or detect any unusual activity.”
Secondly, Monzo has been able to segregate parts of its infrastructure using separate AWS accounts, meaning that if one account were to be compromised, critical infrastructure in other accounts would be unaffected.
These two factors, and other unique offerings from AWS, were some of the many factors that contributed to Monzo securing banking license with restrictions in 2016, allowing it to issue prepaid debit cards, before offering current accounts when these restrictions were lifted in 2017.
AWS has also supported Monzo’s unique software architecture. Rather than using a single, monolithic software package and placing it on the cloud, Monzo was able to design its software from the ground-up, using hundreds of microsystems.
Chris explains that Monzo’s mission to ‘make money work for everyone’ has helped define the principles for its technology: “We knew that a traditional database would have to be scaled vertically and would have an in-built upper limit on capacity.”“Instead, we took the more complex route of a horizontally scalable database, which means we can grow anywhere in the world, with no upper limit on the number of users.”
“The architecture we’ve built on AWS, which we use today for four million customers, is broadly the same as the architecture when we started,” he continues. “We could have cut corners and rushed everything out to market much quicker – instead we futureproofed the technology, so it can evolve as we grow, rather than starting from scratch at different phases of our growth.”
Monzo’s business banking products look set for continued growth, while it’s building on the success of new products like Monzo Plus, which gives users full financial visibility by enabling them to add accounts and credit cards from other banks so they can see them all in the Monzo app.
Chris adds that continued improvements such as this to online banking can have a meaningful impact on the UK.
“By being able to view, spend and categorise their finances more easily, our customers are better-placed to manage their money, they spend less time worrying about it, and they feel more confident when they do spend.”
“That is good for the economy, and good for individuals.”