Nathan Agius is used to responsibility. At 16, he joined a small company to do a tech apprenticeship. Soon he found himself as the sole developer working on the betting software at every racecourse in the UK. Now he’s Head of Engineering for Barclays’ retail mobile app and website. Which means that around 10 million people every day, login to use the tools that his team build.

Nathan says there’s one vital factor to building critical systems in a robust and resilient way. “You have to put engineering first. The technology stack for the Barclays Banking App contains over 100 components. A single piece of code can handle 300m transactions a day. With all that complexity and so much constant change, you have to simplify things into testable chunks. And you have to put your engineers at the heart of the process.”

Nathan first worked with Barclays as an external consultant. When he was offered the chance to join full-time, he was clear what he wanted to do with the opportunity. “My passion was code. I wanted to help Barclays to transform from a big company that bought in multiple, large, third-party tech products to a tech company that approached challenges with an engineering mindset, using the same up-to-the minute technologies and solutions I could use as a developer at home.”

Nathan’s first big impact was the multichannel applications project. The challenge was to take the simple but important tasks that customers could only do in branch and digitise them across multiple platforms. So they became available online, on the mobile app and even on an ATM. 

The desire to make everything in retail banking available as a digital experience is still driving the work Nathan’s team does today.

98% of all customer interactions are digital. So we have to offer our customers an entire digital experience. And we can’t fall back on someone going into a branch or talking to someone on the phone when things don’t work. All of which means keeping pace, with the services our competitors offer, the way our customers live, and the technology they carry in their pockets.

Offering a truly digital experience can also mean offering a truly personal banking experience. At Barclays, we have the opportunity to know individual customers really well, to understand their user habits and banking needs. So we can offer them a more tailored experience, with better advice, prompts and guidance.

“The key is surfacing all that data and making it work for the customer. Ensuring that the data we have is available for customers to help them plan financially, or simply drive their next best action. We also need to use that data to understand what’s most important for our customers and prioritise development projects,” says Nathan.

The multichannel applications concept was about finding ways to offer digital solutions and easy-to-navigate journeys that transformed the user experience for a digital world. But it was also about transforming the way Barclays approached those tech challenges as a team. “Everything I did was aimed at transforming my team to focus on engineering rather than delivery."

If you bring together great people and concentrate on building great quality products, you get the best outcomes in the fastest way possible. That’s why empowering engineers to drive tech forward has always been my passion at Barclays

This engineering approach hinges on defining your solution in terms of logical components that you can test and build. You don’t try to build a whole solution at once. Instead, you get all the parts working first and then fit them together.

This allows you to fail fast and iterate quickly. It means that a component can be tested with users before it becomes part of the broader solution, and that any issues can be debugged before they affect the wider system.

Crucially, it also means that engineers learn from the debugging of each component, making their work more efficient on the rest of the solution, and on every other project going forward.

Dividing your development process into testable chunks leads to another benefit; the output is a set of reusable components for other projects.

“When we created the digital onboarding journey, we built a component that allowed customers to scan their faces, passports or driving licences to identify themselves. During COVID, we repurposed that component to help people register for the mobile app. It meant we could act fast with confidence,” recalls Nathan.

Nathan’s team are now applying this approach on a grand scale. They’ve created a separate team to build and test a library of UI components that all developers can work with. So all the buttons, tables and labels that customers interact with on the Barclays website, or mobile app, come from the same stable.

This engineering ethos influences the way that Nathan and his team look at the whole techstack. With the speed that browser and smartphone technologies are moving, any solution that’s right for today may be obsolete tomorrow. So as well as being reusable, components need to be easily replaceable. And any third-party software we draw on has to work in the same plug-and-play way.   

Simple is a key word in engineering. The more complex you make something, the harder it is to maintain, and the harder it is to replace. You have to build for today, with one eye on the future.

Throughout, the heart of the development process is engineering talent. Which brings us to Nathan’s other great passion – driving social mobility and inclusion.

“Having a diversity of voices, ideas and perspectives makes us a better engineering team. So we work hard to correct the gender and diversity imbalances in the tech industry. And we’re proactive around inclusion. I have a number of people in my team transitioning at the moment. They’ve done some amazing work to raise transgender awareness across our Radbroke campus. And we want to do more around neurodiversity, as some of the best engineers are on the autistic spectrum,” explains Nathan.

Nathan spearheaded an initiative to open a site in Manchester, so that it would be easier for inner-city kids to reach Barclays. And he’s looking at ways to make the Radbroke campus more accessible to the diverse communities nearby.

“I grew up on a council estate in Salford. So I know that working in tech for someone like Barclays can seem a million miles away from your reality.“

He also helped to create an organisation called Manchester Tech Forum that brings together tech leaders across the North-West of England. “Our aim is to forge partnerships that develop talent and deliver growth for the whole region.”   

If you give people opportunities, the results can be spectacular. Heather joined our team recently, from one of Barclays branches. Now she’s working on tech that’s being carried around by 1 in 5 people in the UK. The buttons she built are used by millions of people.

It's the scale and impact of even the simplest components that make the engineering tasks at Barclays so rewarding. And it’s the constant evolution of technology that means there’s always something new to learn.

Engineering that’s fit for the future. It’s happening here.