Senior C++ Programmer

A leading Cambridge technology company is seeking a Lead C++ Engineer to take ownership of a large, business-critical monolithic C++ codebase. This is a rare opportunity to shape the future of a mature system used globally, driving a long-term modernisation programme while embedding world-class engineering and testing practices.

If you enjoy deep technical challenges, architectural thinking, and the satisfaction of turning a complex legacy system into a clean, modern, testable platform, this role will suit you perfectly.

You will become the technical lead responsible for the evolution of a substantial C++ codebase. Your mission spans architecture, refactoring, and quality engineering:

• Modernise a tightly coupled monolith into a more modular, maintainable architecture
• Introduce modern C++ standards (C++17/20), patterns, and tooling
• Lead a structured programme of incremental refactoring and technical debt reduction
• Establish and champion effective testing strategies across the codebase
• Improve testability, reliability, and long-term maintainability
• Drive adoption of CI/CD, automated testing, and static/dynamic analysis tools
• Mentor engineers, lead design reviews, and set engineering standards
• Balance strategic improvements with ongoing feature delivery and maintenance

This is a hands-on leadership role: you’ll write code, shape architecture, and define how quality is engineered into the product.

• Strong expertise in modern C++ and experience working with large, legacy systems
• A deep understanding of refactoring, modularisation, and architectural improvement
• Proven experience designing and implementing robust testing frameworks
• Ability to improve test coverage, introduce automated tests, and enhance CI pipelines
• Experience with unit testing, integration testing, and test-driven approaches
• A pragmatic mindset: improving quality without disrupting delivery
• Strong communication skills and the ability to lead and mentor a team

Nice to have:

• Experience with multithreading, performance optimisation, or low-level systems
• Familiarity with Linux development environments
• Exposure to static analysis, sanitizers, fuzzing, or property-based testing

• High autonomy and ownership of a mission-critical codebase
• A long-term modernisation roadmap you will shape from day one
• A culture that values engineering excellence, testing discipline, and clean design
• Competitive salary, hybrid working, and a Cambridge innovation environment