Principal Software Engineer

As a Principal Software Engineer within the eCommerce Platform Delivery team, you will provide leadership and technical stewardship across multiple squads within a defined Mission. You will be responsible for the overall design and accountable for upholding engineering standards, ensuring the delivery of robust, secure, scalable, and high-performance systems. Your role will involve guiding teams towards technical excellence, fostering a culture of continuous improvement, and driving high performance across all aspects of software development.

Working closely with Product Managers, Agile Delivery Managers, Enterprise Architects, and the Chapter Lead for Software Engineering, you will ensure engineering standards are upheld, guide complex technical solutions, and align strategy, approach, and principles across the Mission. By championing best practices, modern architectures, and innovation, you will accelerate the delivery of customer-facing features, improve platform resilience, and ensure the platform remains robust, scalable, and future-ready.

What you’ll be doing

Own the Mission technical vision, strategy, and roadmap, ensuring alignment with business objectives and platform standards.

Take accountability for technical delivery and execution of the technical vision and strategy across multiple squads.

Lead the design, architecture, and development of scalable, reliable, and high-performance software systems, including system design, technology selection, and overall architecture.

Champion data integrity and performance, ensuring systems are designed for scalability and operational resilience.

Own the delivery of key product features, ensuring they meet performance, security, and scalability requirements.

Ensure the quality of code delivered across squads, adhering to best practices and engineering standards.

Actively contribute to and lead code reviews, providing constructive feedback to continuously improve code quality and team capability.

Utilise metrics and feedback loops to monitor team performance, identify areas for improvement, and drive the continuous development of high-performing engineering teams.

Mentor and provide guidance to junior and mid-level engineers, fostering a culture of continuous learning and improvement.

Stay informed of industry trends, emerging technologies, and methodologies, applying insights to improve software development practices and platform capabilities.

Requirements of the Role

What you’ll bring to the team

Ability to link technical strategy and architectural decisions to measurable outcomes, including feature performance, platform reliability, and customer impact.

Deep knowledge of SQL, databases, data modelling, and performance optimisation.

Proven expertise in cloud and commerce technologies, including AWS.

Strong background in Microsoft technologies, including C# .NET

Extensive experience in observability, leveraging tools for monitoring metrics, telemetry, alerts, and logs to ensure system reliability and performance.

Expertise in data architecture and modelling, with a strong understanding of legacy systems and performance optimisation techniques relevant to operational data platforms.

Proven experience designing and implementing event-driven architectures (EDA) to support real-time data flows.

Strong knowledge of infrastructure and networking principles, with experience in designing and maintaining secure, high-performance systems across distributed platforms.

Extensive software engineering experience with proven capability to lead complex projects and collaborate across cross-functional teams.

Strong understanding of data platforms, with the ability to modernise legacy systems while maintaining reliability and performance.

Deep knowledge of modern design patterns and architectures, including APIs, event-driven architectures (EDA), microapps, front-end frameworks, and app technologies, with experience applying these in eCommerce environments.

What we can offer you

Competitive base salary

Up to 20% bonus

25 days holiday

BAYE, SAYE & Performance share schemes

7% pension

Life Assurance

Flexible benefits package

Excellent staff travel benefits

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