Software Development Engineer III

About the role As a Software Development Engineer 3, you are a senior individual contributor at Tesco specializing in modern front-end development with deep expertise in React and the JavaScript ecosystem. 

Your proficiency in foundational computer science and software engineering concepts is assumed, along with demonstrated capability in building scalable, performant, and user-centric applications. 

At this level, you play an active role in technical leadership within the UI domain, influencing front-end architecture, design patterns, and best practices with a measurable impact across teams and the wider directorate. You take ownership and accountability for the development, quality, and performance of user interfaces in your domain, ensuring high standards in accessibility, responsiveness, and maintainability. You participate in building organisational capability through mentoring and coaching engineers, conducting code reviews, and supporting hiring and interviewing efforts. 

You will be responsible for My impact reaches beyond my immediate team, and I provide perspective and context for technology choices across my directorate. The work that I do has foundational impact across teams in my area and the directorate that I am a member of. I am a technical leader for my teams and others will regularly come to me for mentorship and support. I am comfortable both supporting other engineers in their delivery and taking the lead on key features as appropriate. I have delivered multiple projects that move the needle for the business. I have demonstrated technical breadth and depth; I am an expert in my domain.

At this level I display a high degree of ownership for the work conducted by the team. I am accountable for the quality of every result, produced by individuals and teams. I am an advocate of best practices across my directorate. I build maturity in the way we develop, deliver and operate services. I ensure that we’re learning from the best in the industry, designing and implementing appropriate testing and deployment strategies.

I can anticipate feature evolution of my product. I utilise this when facilitating design sessions to ensure that the system architecture evolves to support future requirements. I understand the wider Tesco architectural strategy and champion its application to the systems that I work on. At this level my job starts to become just as much about exercising technical judgment as it does about implementation.I am comfortable managing competing priorities and am able to bring order to ambiguous scenarios. I create optimal outcomes combining short-term and long-term goals, utilising data driven decision making techniques to take appropriate trade-offs. I can identify risks and proactively engage with product and programme managers. I am a strong communicator within my team and to my stakeholders.

I am a trusted mentor, a role-model for more junior engineers. I am approachable and am frequently asked to mentor those around me. I prioritise sharing skills and technical knowledge across the directorate, both informally in 1:1 discussions and by arranging more formal training opportunities.I build capability and raise the bar by contributing to hiring and interviewing practices. I regularly participate in recruitment assessments. Externally I represent the best of Tesco Technology to attract new talent and encourage interest in our organisation.

You will need

• React Core & Hooks Mastery (useState, useEffect, useMemo, useCallback, custom hooks)
• Advanced React Concepts (reconciliation, rendering behavior, Suspense, lazy loading)
• Component Design Patterns (composition, reusable components, HOC, render props)
• State Management (Context, Redux Toolkit, React Query/server state)
• TypeScript in React (generics, strong typing, scalable component APIs)
• Performance Optimization (memoization, code splitting, virtualization, profiling)
• Advanced JavaScript Fundamentals (closures, async flows, immutability, event loop)
• Frontend Architecture (scalable folder structure, modular design, design systems)
• API Integration (REST/GraphQL, caching, error handling, async data patterns)
• Testing (Jest, React Testing Library, E2E basics like Cypress/Playwright)
• Styling & UI Systems (CSS, Flexbox/Grid, Tailwind/Styled Components, theming)
• Routing & Navigation (React Router, guarded routes, dynamic navigation)
• Accessibility (a11y) (ARIA, keyboard n…