C# Software Engineer (Security Clearance)

C# Software Engineer (Security Clearance)

Position Description
The Space, Defence and Intelligence business unit in CGI is a true IT Systems Integrator. We work, build, and operate bespoke, technically complex, mission-critical systems which help our clients keep us all safe and secure. We bring innovation to our clients using proven and emerging technologies, agile delivery processes and our deep expertise across the breadth of space, defence, intelligence, aerospace and maritime, all underpinned by our end-to-end cyber capability. We work collaboratively with global technology companies, cutting edge SMEs and academia to deliver the optimal solution for each client.

CGI was recognised in the Sunday Times Best Places to Work List 2025 and has been named one of the 'World's Best Employers' by Forbes magazine. 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 Forces 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 secure nature of the programme, you will need to hold UK Security Clearance or be eligible to go through this clearance. This position will be a hybrid position, working out of our site in Leatherhead or Reading.

Your future duties and responsibilities
Our system is a mix of hosted and remote-deployed environments across various sites worldwide. We are transitioning to a new platform built on Azure local with Windows Server 2016, 2022 and Microsoft SQL Server 2022, supporting bespoke COTS medical software and infrastructure.

Our client now wants to integrate some new (separate) capabilities with our existing platforms and services. This will require the update and improvement to a series of API interfaces to allow the client to operate an ecosystem of medical capabilities.

As a C# Developer, you will play a critical role in updating our current systems and APIs to allow the movement of data between our systems and the new client systems.
You will work within a DevOps environment to uplift existing software, develop new modules, and support tightly integrated COTS and infrastructure components including Microsoft Office, Adobe Reader, and peripheral hardware like printers and scanners.

You will contribute to system improvement while ensuring all changes align with Quality of Service and SLA expectations. Your input into process optimisation, testing, and system configuration will be highly valued.

Key Responsibilities:

• Uplift and enhance the legacy medical software (including APIs) to align with modern standards.

• Develop new features/ modules where required to support operational requirements.

• Ensure all code is placed under version control and adheres to best practices.

• Write and execute unit tests; collaborate with QA to refine system testing.

• Support build, configuration, and deployment of operating system images.

• Collaborate with infrastructure and support teams to address system-wide enhancements.

Required qualifications to be successful in this role
• Strong background in C# development with Visual Studio 2019 and git.

• Hands-on experience with Windows Server 2016 and above environments.

• Solid experience working with Microsoft SQL Server 2017 and above.

• Familiarity with COTS integration, especially Microsoft Office 2016 and Adobe products.

• Configuration control experience using SVN or similar tools.

• Ability to understand and navigate complex, safety-critical systems.

• Exposure to Agile (SAFe) methodologies and DevOps practices.

Desirable Experience:

• Operating system and application security hardening techniques.

• Active Directory and Group Policy Object (GPO) configuration.

• Security and compliance tooling such as Nessus.

• Knowledge of UPS systems and their interaction with Windows.

• Experience building and deploying custom OS images (ISOs).

• Familiarity with Bugzilla for issue tracking and management.

• Exposure to Ansible, Jenkins and RunDeck

• Exposure to Microsoft COM/ COM+ based technologies

#LI-SB2

Together, as owners, let's turn meaningful insights into action.

Life at CGI is rooted in ownership, teamwork, respect and belonging. Here, you'll reach your full potential because...

You are invited to be an owner from day 1 as we work together to bring our Dream to life. That's why we call ourselves CGI Partners rather than employees. We benefit from our collective success and actively shape our company's strategy and direction.

Your work creates value. You'll develop innovative solutions and build relationships with teammates and clients while accessing global capabilities to scale your ideas, embrace new opportunities, and benefit from expansive industry and technology expertise.

You'll shape your career by joining a company built to grow and last. You'll be supported by leaders who care about your health and well-being and provide you with opportunities to deepen your skills and broaden your horizons.

Come join our team-one of the largest IT and business consulting services firms in the world.