Software Engineer (C++) in Gloucester

At CGI, we’re redefining what’s possible in the Space, Defence, and Intelligence sector delivering secure, mission‑critical systems that protect the UK and drive national capability. As a C++ Software Engineer, you’ll help design and implement next‑generation solutions that enable operational excellence and resilience in the most demanding environments.

You’ll be part of a trusted team that values innovation, ownership, and collaboration—empowering you to shape the future of defence technology while advancing your own career through continuous learning and professional growth. CGI was recognised in the Sunday Times Best Places to Work List 2025 and has been named a UK ‘Best Employer’ by the Financial Times. We offer a competitive salary, excellent pension, private healthcare, plus a share scheme (3.5% + 3.5% matching) which makes you a CGI Partner, not just an employee.

We are committed to inclusivity, building a genuinely diverse community of tech talent and inspiring everyone to pursue careers in our sector, including our Armed Forces, and are proud to hold a Gold Award in recognition of our support of the Armed Force Corporate Covenant. Join us and you’ll be part of an open, friendly community of experts. We’ll train and support you in taking your career wherever you want it to go.

Due to the highly secure nature of the work, this role is only open to sole UK Nationals who hold or are eligible to hold High‑Level Clearance (HLC). While hybrid or remote working may be possible, regular attendance at the secure site will be required.

Your future duties and responsibilities

In this role, you will engineer high-performance, secure software systems that underpin mission‑critical defence operations. You’ll collaborate with clients and cross‑functional teams to design, develop, and deliver robust solutions that meet exacting standards of performance and reliability. Your expertise will directly influence the success of strategic projects, ensuring our clients maintain a technological edge in national security.

You’ll take ownership of your work from concept through delivery, bringing creativity and precision to every challenge. Supported by CGI’s collaborative culture, you’ll have opportunities to innovate, contribute to technical direction, and build a rewarding, purpose-driven career.

Key responsibilities

• Design & develop high‑quality, modern C++ software solutions aligned with mission objectives.
• Collaborate & innovate: work closely with multidisciplinary teams and clients to translate technical requirements into effective solutions.
• Optimise & secure: apply secure coding standards, performance optimisation, and rigorous testing practices.
• Deliver & evolve: contribute to Agile ceremonies, CI/CD pipelines, and continuous improvement initiatives.
• Document & communicate: produce clear technical documentation and contribute to knowledge‑sharing across teams.

Required qualifications to be successful in this role

You should have strong experience developing secure, high-performance software using modern C++ and be passionate about delivering reliable systems that make a real difference. A background in defence, aerospace, or similar high‑assurance environments is advantageous but not essential.

Essential qualifications

• Proven experience with modern C++ (C++11 and above) and OOD principles.
• Solid understanding of multithreading, concurrency, and real‑time software design.
• Familiarity with Linux and cross‑platform development environments.
• Experience with CI/CD tools, version control, and unit testing frameworks.
• Awareness of secure coding standards and best practices.
• Strong analytical and problem‑solving skills, with the ability to work effectively in collaborative teams.

Desirable qualifications

• Experience in embedded or mission‑critical systems.
• Knowledge of middleware technologies (e.g., DDS, ZeroMQ) and scripting (Python, Bash).
• Understanding of Agile delivery models such as Scrum or SAFe.