Senior R Developer - London

About The Role

FDM is a global business and technology consultancy seeking a Senior R Developer / Software Engineer to work for our client within the public sector. This is initially a 4- month contract with the potential to extend and will be a hybrid role that will be based in London

We are seeking an experienced Senior R Developer / Software Engineer to support the enhancement and modernisation of critical data and reporting solutions. The successful candidate will play a key role in upgrading existing platforms, reducing technical debt, improving application performance, and ensuring the ongoing reliability of business-critical systems.

This role requires a strong software engineering mindset, combining advanced R development expertise with a focus on testing, automation, quality assurance, and scalable data solutions.

Key Responsibilities:

• Design, develop, maintain, and enhance complex applications and data solutions using R.
• Refactor legacy codebases to improve maintainability, performance, scalability, and code quality.
• Modernise existing systems and migrate applications to newer technology platforms.
• Develop and maintain data transformation pipelines that support reporting and analytical requirements.
• Create and manage reusable R packages, libraries, and software components.
• Implement software engineering best practices, including version control, code reviews, documentation, and automated deployment processes.
• Optimise application performance and resolve technical debt across existing solutions.
• Collaborate with technical and business stakeholders to understand requirements and deliver robust solutions.
• Ensure continuity and consistency of outputs when implementing system improvements or platform changes.
• Design and execute comprehensive testing strategies, including regression testing, reconciliation activities, and automated validation processes.
• Develop quality assurance frameworks to ensure code changes are thoroughly tested and do not impact established outputs.
• Support the enhancement of reporting and analytical capabilities through improved data models and processing logic.
• Contribute to proof of concepts and innovation initiatives using modern cloud and analytics technologies.

About You

• Extensive experience developing and maintaining complex applications using R.
• Strong understanding of software engineering principles and best practices.
• Experience building and maintaining data transformation and processing pipelines.
• Proven experience creating and managing R packages and reusable code frameworks.
• Experience developing proof-of-concept solutions using Databricks.
• Understanding of modern data engineering, cloud analytics, and scalable data architectures.
• Experience designing and delivering Power BI dashboards and reports.
• Experience maintaining and modernising business-critical reporting platforms.
• Strong understanding of data modelling and reporting workflows.
• Experience refactoring legacy systems while maintaining output consistency and reliability.
• Tech Stack: R, SQL, Git/Azure DevOps, Power BI, Databricks, Python, Microsoft Power Platform and Excel.

About Us

FDM is an award-winning global leader in tech and business talent solutions, backed by more than 35 years of industry experience. We have centres across Europe, North America, and Asia-Pacific, and a global workforce of over 2500 employees. FDM has shown exponential growth throughout the years, firmly establishing itself as an award-winning employer, currently listed on the FTSE4Good Index and as a 2026 Financial Times UK 'Best Employer'.

Why join us

• Career coaching, mentoring and access to upskilling throughout your entire FDM career
• Assignments with global companies and opportunities to work abroad
• Opportunity to re-skill and up-skill into new areas, develop non-linear career paths and build a skillset within your field
• Annual leave and work-place pension