Software Development Engineer III in London

Our vision at Tesco 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.

The Product & Engineering team is responsible for designing, building and scaling Data & AI products that power intelligent experiences, decisions and actions across the Tesco ecosystem. Working in close partnership with business and technology teams across Stores, Finance, People, Customer and Commercial, we enable these 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 Tesco 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.

You will be responsible for:

• The Software Development Engineer III is a senior, hands-on engineer specialising in building and operating GenAI powered products, including LLM based applications and agentic workflows that enable intelligent decision making and automation.
• The role spans the full product lifecycle, translating complex business problems into production grade solutions across data, backend services, APIs and user facing applications, with a strong focus on reliability, guardrails and real user impact.
• The role also provides technical leadership by designing shared GenAI capabilities, supporting live systems and raising engineering and AI delivery standards across the team through mentoring and rigorous design practice.

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.

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.

What's in it for you:

• Annual bonus scheme of up to 20% of base salary
• Holiday starting at 25 days plus a personal day (plus Bank holidays)
• Private medical insurance
• 26 weeks maternity and adoption leave (after 1 year service) 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