Senior Full Stack Engineer

RSMB is seeking an experienced and highly capable Senior Full Stack Engineer to play a central role in the design, development, and evolution of our expanding product suite, including Barb Ads Hub, NMO XCM, and our Data Fusion platform. You will join the team based in London (Hybrid – 2 days per week in the office) on a full-time, permanent basis, and in return, you will receive a competitive salary of up to £85,000 per annum, based on experience.

RSMB is a leading company specialising in media measurement solutions. We work with a wide range of clients delivering both long-term contracts like Barb (UK TV audience measurement) and RAJAR (Radio audience measurement), and ad hoc projects. Our team of around 50 people are based in Central London, and we are currently operating hybrid working: splitting the week between home and office working.

The Senior Full Stack Engineer role sits within the Development team in the Technology department and is critical to delivering scalable, high-performance, data-driven products. You will work across the full stack, contributing to backend services, APIs, and frontend applications, while collaborating closely with data science, product, and external partners to deliver robust, user-focused solutions.

Key responsibilities as our Senior Full Stack Engineer will include:

• Full Stack Development & System Design: Designing and building scalable, maintainable, and high-performance applications across backend and frontend layers. Developing backend services using Python and SQL, with integration into Azure-based infrastructure and Snowflake data platforms. Building intuitive, performant front-end interfaces using React and modern JavaScript/TypeScript frameworks. Contributing to architecture decisions across multiple products, ensuring consistency, scalability, and long-term maintainability. Designing and developing APIs for internal and external consumption.
• Data Platform & Product Engineering: Working on data-intensive products, including Data Fusion and analytics platforms, handling large-scale datasets and complex transformations. Collaborating with data scientists to productionise models, pipelines, and analytical workflows. Designing data models, pipelines, and query strategies to support performant analytics and reporting use cases. Ensuring data quality, integrity, and observability across systems.
• Delivery & Engineering Excellence: Taking ownership of features from design through to deployment and ongoing iteration. Working within agile development processes, contributing to sprint planning, estimation, and continuous improvement. Writing clean, well-tested, and maintainable code, with strong emphasis on automated testing and CI/CD practices. Contributing to engineering standards, code reviews, and best practices across the Development team.
• Cross-functional Collaboration: Working closely with Product Managers, Data Scientists, QA, and Technical Leadership to deliver high-quality products. Collaborating with external partners, clients, and industry stakeholders where required. Translating complex data and technical requirements into scalable engineering solutions.
• AI-Enabled Development Practices: Effectively integrating AI-assisted development tools (e.g., code generation, testing, debugging, documentation) into day-to-day workflows. Applying critical judgement to ensure correctness, security, and maintainability of AI-assisted outputs. Continuously evaluating emerging AI tools and practices to improve engineering efficiency and quality.

What we are looking for in our Senior Full Stack Engineer:

• Proven experience (typically 5–10+ years) in full stack software engineering, ideally within data heavy, analytics, or SaaS environments.
• Strong backend development experience with Python and SQL (relational and/or analytical databases).
• Experience working with cloud platforms, particularly Azure.
• Experience working with modern data platforms such as Snowflake (or similar analytical warehouses).
• Experience with .NET is desirable.
• Strong frontend development experience using React and modern JavaScript/TypeScript.
• Experience designing and building APIs and distributed systems.
• Solid understanding of data engineering concepts, including data modelling, ETL/ELT pipelines, and performance optimisation.
• Experience with CI/CD, containerised systems, and modern deployment workflows.
• Familiarity with working alongside data science teams and deploying data-driven products.
• Experience working in agile environments (Scrum/Kanban) with strong ownership of delivery.
• Strong problem-solving skills and ability to work with complex, data-rich systems.
• Excellent communication skills and ability to collaborate across technical and non-technical stakeholders.

What you'll get in return as our Senior Full Stack Engineer:

• A central role in building industry-leading platforms such as Barb Ads Hub, NMO XCM, and Data Fusion.
• Opportunity to work on complex, high-impact data and analytics products used across the media ecosystem.
• Exposure to cutting-edge work in data integration, analytics, and measurement.
• Hybrid working model (2 days per week in our Central London office).
• A collaborative environment with strong engineering and data science expertise.
• 25 days holiday rising to 30, private medical insurance, pension, season ticket loan and more.

If you feel you have the skills and experience to become a Senior Full Stack Engineer in this exciting role, then please click “apply” now – We’d love to hear from you! Please note that applicants must have the right to work in the UK. We are not accepting unsolicited agency applications for this role.