Principal Software Engineer - Service Experience in City of Westminster

We are seeking a passionate Principal Software Engineer who will provide technical expertise, ship thoughtfully and operate with excellence. Being creative, curious, and fearless, you will be an integral part of our empowered, self-managing, multi-disciplinary engineering teams - designing, building, releasing, and maintaining products. Working as an equal partner with the Product and Delivery teams you will deliver sophisticated and robust solutions to solve ambitious problems for our customers and colleagues.

You will play a key role in driving our ambition to create a best-in-class software engineering team, environment, and culture. We are looking for people to join our community of engineers to drive this transformation, build a modern digital ecosystem using exciting technologies and do the best work of their careers.

You will be championing Engineering excellence in a key area for M&S, that enables our online customers to pay, take delivery and return products. As the Principal Engineer for Service Experience, you will support multiple teams in providing a seamless digital experience to M&S customers when it comes to payments, order fulfilment, self-service and returns. This is integral to delivering the best online purchasing experience in the UK and Irish market, to attain, retain and drive frequency of customers and aligns with the broader omni-channel experience to deliver the M&S unified customer commerce ambition.

What you will be doing:

• Lead and scale high-performing engineering teams to build secure, reliable, and resilient solutions from development through to launch and operation.
• Drive engineering excellence and continuous improvement, including DevOps practices, clean code/architecture, DORA metrics, and operational quality.
• Set technical direction and influence technology and product strategy, crafting investment decisions, team structures, and platform adoption.
• Foster a culture of innovation, efficiency, and autonomy by mentoring engineers, championing communities of practice, and leading by example.
• Improve delivery efficiency through modern ways of working, automation, and platform-led approaches that increase value at pace.
• Partner closely with Engineering, Technology, and Product leadership while supporting hiring, onboarding, brand advocacy, and the wider engineering ecosystem.

Tech stack:

• Service Experience is predominantly a back-end area, with some front-end applications.
• React, Next.js, Typescript, Optimizely
• Java, Spring, Spring Boot, Micronaut, GraphQL, Kafka
• MongoDB, Postgres, Redis
• Azure, Kubernetes
• Dynatrace
• GitHub Actions

What you need to have:

• Demonstrated history of strategic, innovative thinking with the ability to complete and deliver complex, high-impact engineering initiatives.
• Deep expertise in modern, web-based software engineering, including clean code, building patterns, system development, and performance engineering across devices.
• Strong authority in cloud platforms and automation (e.g., Kubernetes, serverless, networking, security) with experience in observability, reliability, and testing at scale.
• Advanced knowledge of information security, quality assurance, and reliability engineering, with the ability to develop and ensure secure, resilient systems.
• Demonstrated ability to lead and influence senior engineers and stakeholders across multiple teams, collaborating with the Staff Engineer to steer complex technical and non-technical build decisions without dictating outcomes.
• Experience optimizing processes and services end-to-end, mentoring specialists, crafting technical strategy, and aligning delivery with wider business and technology goals.

What’s In It For You:

Working at M&S means being part of something bigger - helping to deliver quality, value and service to millions of customers every day. We’re inclusive, fast-moving and always evolving, with a strong sense of purpose and a focus on doing the right thing.

Here are just a few of the benefits that make working here even more rewarding:

• 20% colleague discount on all M&S products and many third-party brands for you and someone in your household, available once you’ve completed your probation
• Competitive holiday allowance with the option to buy more
• Discretionary bonus schemes linked to your performance and ours
• Strong pension and life assurance to help plan for the future
• Tailored induction and training to support your development from day one
• Exclusive perks and savings through our M&S Choices portal
• Market-leading family policies, including parental, adoption and neonatal leave
• 24/7 wellbeing support, including virtual GP access and mental health services
• One paid volunteer day a year to support a cause that matters to you

Everyone’s Welcome:

We are ambitious about the future of retail. We’re disrupting, innovating and leading the industry into a more conscientious, inspiring digital era. We’re transforming how we work together and offering our most exciting opportunities yet. Marks & Spencer strives to be an inclusive organisation, trusted and admired by our colleagues, customers and suppliers. Join us and make change happen.

We are committed to building diverse and representative teams, where everyone can bring their whole selves to work and be at their best. We support each other and work together to win together.

If you feel you’d benefit from any support or reasonable adjustments during any stage of the recruitment process, please don’t hesitate to let us know when completing your application. This information will be picked up by our team, so we can try and put steps in place to help you be at your best through this process.