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Case study: Nationwide

State of Open: The UK in 2022

Phase One “The Open Source Journey”

Seiji Okamoto, Cloud Platform Engineer at Nationwide Building Society


Nationwide Building Society, a UK pioneer in digital banking, embarked on a digital transformation in 2008, investing £4.1 billion in upgrading its systems with a focus on Apache Kafka for streaming data. With a workforce of 18,000, including 6,000 engineers, Nationwide embraces Open Source software for its cost-effectiveness. Aiming to create a uniform engagement platform, the team utilises diverse Open Source technologies, but as a consumer, they face challenges in contributing back to the Open Source community. Nationwide seeks to deepen engagement, contribute to the community, and increase awareness of Open Source practices within the organisation for continued digital evolution

4.3 Case Study – Nationwide Building Society

Seiji Okamoto, Cloud Platform Engineer at Nationwide Building Society

Banking systems have historically run on-premises (on-prem) akin to expensive data centres within banks. Cut to 2022, banking systems have become modular layers in the cloud, enabling various components to be provided as a service, reliant on Open Source Software. Once such a bank is Nationwide Building Society.

Nationwide Building Society

Based in the UK with over 18,000 employees including 6,000 engineers, Nationwide is a pioneer in digital banking. Seiji Okamoto, Cloud Platform Engineer explained their journey. Digital transformation began in 2008, when Nationwide launched a project to transform its technology and upgrade its data centres. £4.1Bn investment in re-architecting systems around the streaming data technology Apache Kafka, has facilitated speeding up access to transactional data and increased resiliency.

Their overall digitalisation effort uses a mixed bag of technologies including Open Source Software. “It’s very cost effective to use Open Source Software for our team. There’s four of us, and we can’t possibly write vast amounts of code. If there’s tooling that exists, it makes more sense to utilise and reuse it”

A collaborative platform

Seiji and his team are creating a uniform engagement platform combining multiple tooling elements across the business into one shared platform. This allows developers to leverage the platform to. Open Source Software is in play across libraries, container cloud native technologies, databases, observability tools, security tools, software build tools and operating systems like Linux. Seiji notes that, “when Nationwide explores a new tool, one of the first things we’ll look at is open source.”

The Open Source Software journey in finance

As a consumer of Open Source Software not a contributor, Nationwide comes up against some challenges in its use, mainly related to maintenance concerns, such as if their tool needs a new feature, it’s tricky to raise a feature request with the maintainer and achieve rapid results if you are not engaged. Seiji recognises that they need to evolve their relationship with Open Source Software and interact with the relevant communities at a deeper level.

He says, “we’re trying to draft how we can contribute to the community, as in finance, as a regulated sector we need bespoke software to increase security.” They also need internal approvals and appropriate policies and this desire to engage further creates a desire to mature and shift towards contributing back to the open source being used.

In terms of policies as a consumer of Open Source Software, Nationwide has a robust security process in place for adopting any new digital tools. Initially all suitable open source tools are evaluated with an analysis of the benefits, concerns and risks of each alternative. Senior and lead engineers review the analysis to make an informed decision. Seiji feels that it is critical to do more, especially at the very start of using an open software tool, when “There’s a lot of security checks around things that are being run to make sure that any packages work sufficiently. It’s much better to catch issues earlier on, for example in the build process, or the commit process.”

Moving forward

Seiji feels there is awareness about Open Source Software in Nationwide but there is always room to do more and shape the journey ahead as more contributions occur. “I’m hoping to make Open Source Software much more obvious and visible within the engineering teams and the wider business – so that they’re more aware of what it is that we’re doing and how we’re doing it. I’d really love to see what we can do to contribute back more as an organisation to the community.”

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