Full job descriptionA 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.
The RoleYou 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.
What You’ll Bring*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
Why Join*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