Software Development Engineer III

Software Development Engineer III

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[Employer hidden — sign up to reveal] UK • London • Hybrid • Full-Time • Working hours 36 • Apply by 15-May-2026

About the role

The Product & Engineering team is responsible for designing, building and scaling Data & AI products that power intelligent experiences, decisions and actions across the [Employer hidden — sign up to reveal] ecosystem. Working in close partnership with business and technology teams across Stores, Finance, People, Customer and Commercial, we enable the seamless build, integration and adoption of Data & AI capabilities that deliver measurable value. This is an opportunity to play a leading role in shaping a new generation of Data & AI products, from problem definition through to launch and scale, driving meaningful impact for [Employer hidden — sign up to reveal] colleagues and the wider business. This is a hybrid role with the expectation of being based at our London and Welwyn Garden City offices 3 days a week.

What is in it for you

We’re all about the little helps. That’s why we make sure our [Employer hidden — sign up to reveal] colleague benefits package takes care of you – both in and out of work. Click Here to find out more! Annual bonus scheme of up to 10% of base salary. Holiday starting at 25 days plus a personal day (plus Bank holidays). 26 weeks maternity and adoption leave (12 months service required at the qualifying date) at full pay, followed by 13 weeks of Statutory Maternity Pay or Statutory Adoption Pay, we also offer 6 weeks fully paid paternity leave. Free 24/7 virtual GP service, Employee Assistance Programme (EAP) for you and your family, free access to a range of experts to support your mental wellbeing. The above information is a shortened summary, refer to our policies for full details.

You will be responsible for

• Data & AI Product Development: Take ideas from discovery through rapid prototypes to production grade solutions that combine data, user facing applications and backend services.
• Work closely with product managers, designers, data science and engineering teams to translate business needs into well designed technical solutions.
• Design and deliver LLM based applications and AI agents that enable intelligent decision making and automation, applying pragmatic engineering patterns and appropriate guardrails.
• Design and consume APIs that support responsive, intuitive UIs, working across backend, data and frontend layers to deliver coherent, production-ready experiences.
• Build shared capabilities (libraries, templates, services, prompts/config patterns, evaluation suites) that reduce duplication and enable other squads to adopt GenAI safely and consistently.
• Support and operate live systems, troubleshoot complex issues, perform root cause analysis and continuously improve reliability, quality and speed of delivery.
• Build and maintain web-based user interfaces using React.js, modern JavaScript / TypeScript, HTML and CSS, enabling colleagues to interact effectively with data and AI based tools.
• Technical Excellence: Promote strong software engineering practices across backend and frontend development, including CI/CD, testing, secure by default development, performance optimisation and observability.
• Support and operate live systems, troubleshoot complex issues, perform root cause analysis and continuously improve reliability, quality and speed of delivery.
• Technical Leadership: Provide hands-on technical leadership through design reviews, mentoring and knowledge sharing, helping raise engineering standards across the team.

You will need

• Strong experience as a senior software engineer delivering and operating production systems.
• Solid backend engineering experience (e.g. Python or similar), including API design, testing, CI/CD and operational support.
• Practical experience building LLM-powered applications (e.g. copilots, assistants, agent based workflows), with a focus on reliability and real user impact.
• Good working knowledge of React.js and modern JavaScript / TypeScript, with experience building and maintaining production web interfaces.
• Proficiency with HTML and CSS, and an understanding of usability, accessibility and performance considerations.
• Experience working across data, backend and UI layers, collaborating with others rather than owning every layer in isolation.
• Ability to make thoughtful technical trade offs, communicate clearly with both technical and non technical stakeholders and work effectively in a product led team.

About us

Our vision at [Employer hidden — sign up to reveal] is to become every customer's favourite way to shop, whether they are at home or out on the move. Our core purpose is ‘Serving our customers, communities and planet a little better every day’. Serving means more than a transactional relationship with our customers. It means acting as a responsible and sustainable business for all stakeholders, for the communities we are part of and for the planet. We are proud to have an inclusive culture at [Employer hidden — sign up to reveal] where everyone truly feels able to be themselves. At [Employer hidden — sign up to reveal], we not only celebrate diversity, but recognise the value and opportunity it brings. We're committed to creating a workplace where differences are valued, and make sure that all colleagues are given the same opportunities. We’re proud to have been accredited Disability Confident Leader and we’re committed to providing a fully inclusive and accessible recruitment process. For further information on the accessibility support we can offer, please click here. We’re a big business and we can offer a range of diverse full-time & part-time working patterns across our many business areas, which means that we can find something that works for you. We work in a more blended pattern - combining office and remote working. Our offices will continue to be where we connect, collaborate and innovate. If you are applying internally, please speak to the Hiring Manager about how this can work for you - Everyone is welcome at [Employer hidden — sign up to reveal].