Monzo Bank eyes AWS managed services so that it can focus on banking

Profile picture for user Sooraj Shah By Sooraj Shah December 5, 2019
Monzo Bank’s platform team lead Chris Evans and senior software engineer Suhail Patel explain why they’re going to tap into more of AWS’s managed services offerings

Monzo logo and mobile app - composite of Monzo images

Monzo was founded in 2015, and in four years has grown steadily, amassing 1.7 million users, with more than £1bn made in transactions so far. It was very much in its early days that the company decided to use Amazon Web Services (AWS) as its infrastructure, and this was largely motivated by the cloud computing company’s willingness to work with the Financial Conduct Authority and the regulators in the UK to ensure that the bank could run in the cloud, which hadn’t been possible previously.

The company runs more than 400 banking microservices on AWS, and uses AWS EC2, EBS and S3. Chris Evans, the Monzo’s platform team lead, tells diginomica that AWS is the core of all of the company’s technology. He said:

AWS allows us as a platform team to be super agile. From a customer point of view, it’s the fact that ideas that people have at the company at the product level are just things we can aggressively go after – we are incredibly fast to market with ideas, it’s staggering compared to other companies in the industry”.

What we do as a team is layer on top of that layer a bunch of platforms and components that we then offer to our engineers internally. A good example of that is we take EC2, and then we run our own Kubernetes clusters on top of that and then we offer that to our engineers as a managed-type platform internally.

Suhail Patel, senior software engineer at Monzo Bank added:

Our role is to layer a set of services on top of AWS so that engineers are most effective in their roles and don’t have to worry about infrastructure, they can worry about growing a better bank. 

Currently, Evans’ team uses many core AWS services and they turn these into a platform themselves. However, at AWS re:Invent in Las Vegas, AWS announced several management tools including AWS Fargate for EKS, and Amazon Managed (Apache) Cassandra Services, that Monzo could be interested in using.

Evans said:

They can now provide a managed Kubernetes services, and a managed Kafka service and a managed Cassandra service, and these are really core components of the bank and there’s a decision to be made around whether we continue running things ourselves or whether we realise we have three people working on Kafka versus an entire AWS team dedicated to that. Does it make sense to run it ourselves?

Essentially the team could be spending their time working on other areas of the business.

Evans said:

I would love to be able to throw really gnarly problems that are really specific for us as a bank, trying to solve some complex customer problem. We’re just treading that line at the moment – so there’s a lot of things we do which are just an operational burden because we run these things ourselves.

However, Evans does not consider vendor lock-in as an issue; Monzo’s data and analytics are based in Google Cloud Platform, for example. Although multi-cloud is not something that the bank is considering at the moment – he imagines going multi-region before going multi-cloud.

A bigger concern than vendor lock-in for Evans is around management. He said:

If something goes wrong, then something goes wrong and it’s fully out of our control. It’s a service offering and we’d be unable to do anything about it. So, if we’re using a managed Cassandra and had some form of issue, we can’t jump in and fix it – and we can’t provide updates to the regulator about what’s going on, other than what support tells us from AWS.

Keeping ahead of the competition

While Monzo may have had a head start with regards to cloud compared to traditional companies, there are new fintech companies appearing with increased frequency – so how does Monzo Bank ensure that it is able to keep up with these newer firms?

Evans said:

I don’t think there’s anything that a new company or fintech would be deploying that would be radically different. I would imagine people starting in this kind of space would probably start on a more managed journey as the offerings are more mature. We’ll probably transition partly towards that direction anyway.

He emphasised that this was one of the things that kept him up at night – falling into the trap of feeling like Monzo is ahead of the curve and then waking up one day and being like a traditional bank where it’s hard to change the technology stack. However, he doesn’t have any concerns right now.

To ensure that his team keeps up, he said that they are always keeping their eyes on emerging technologies and trends, and perhaps the easiest way to check that the business is always ready is with its agility.

Evans explained:

If we get to the point where someone says ‘I want to offer this to a customer’ and we go ‘well, we can’t do that’. Then that’s a red flag.

This hasn’t happened yet, and Evans and Patel will be hoping this remains the same for many years to come.