Senior C++ Developer (Contract)

Employment type: Contract. Contract Senior C++ Developer Location: London, 2 to 3 days onsite in Kings Cross Contract: Immediate start - 6 month contract Who We Are AND Digital are on a mission to close the world's tech skills gap. We help organisations navigate the future of technology by combining human expertise, emerging tech and AI to deliver better outcomes, faster. Since 2014, we've worked alongside clients to solve complex challenges, build high-performing teams and create lasting capability. Today, we're over 1,300 people across the UK, Europe and the USA, with ambitious plans for continued growth. The Role We're looking for four Embedded C++ Developers to join an in-house backend engineering team working on a highly regulated, safety-critical medical technology product. You'll own a self-contained area of the application, taking work from initial design through to merged, tested and documented code. Depending on your experience and the team's needs, this could include areas such as alarms, patient data persistence, device supervision and start-up, session management or service functionality. You'll work closely with the Software Architect and engineers responsible for surrounding components, while taking ownership of delivery within your area. This role is well suited to an experienced Embedded C++ Engineer who has worked on Linux-based safety-critical, mission-critical or highly regulated products and is comfortable working with formal quality processes, static analysis, code coverage and rigorous testing requirements. What You'll Be Working On Your work could span a number of areas of the embedded application, including: Alarms Developing technical alarm conditions based on hardware and operating system telemetry. Working with signals including battery, temperature, clock, power faults and telemetry quality. Implementing patient sensor, signal quality and external monitoring alarms. Working with hardware alarm interfaces including mute functionality, alarm-level verification and alarm telemetry. Building robust fault handling and recovery mechanisms. Start-Up, Self-Test & Supervision Developing power-on checks covering logging, hardware compatibility, GPU checks and system self-tests. Implementing fail-safe states and fault management. Integrating watchdog and system supervision mechanisms. Supporting interrupted-session detection and recovery. Developing logging, audit logging and log rotation functionality. Working with OS telemetry including power button and storage health monitoring. Patient Data Persistence & Presentation Developing storage interfaces supporting atomic and checksummed writes. Managing reading, deletion and session listing across fixed storage partitions. Building patient-data packaging, queueing, flushing, retention and retrieval functionality. Supporting data back-fill and historic data presentation. Developing versioned interfaces between backend data and the GUI. Session Lifecycle, Power-Down & Service Managing patient sensor and session lifecycles. Supporting session metadata, recovery and graceful shutdown. Developing power-button handling and controlled power-down functionality. Supporting USB data export functionality. Working with service tools and device service handlers. Supporting software updates, confirmation and rollback. Implementing log extraction and audit logging. Essential Skills & Experience Strong experience developing modern C++17 applications on embedded Linux. Strong understanding of RAII, fixed-width types, std::atomic, multithreading and lock-free or bounded queues. Experience developing software where deterministic behaviour and reliability are critical. Experience with allocation-free or low-allocation runtime environments, including pre-allocated memory and fixed-capacity containers. Experience with ports-and-adapters / hexagonal architecture, interfaces and dependency injection. Strong Linux systems integration experience, including services, watchdogs and system-level fault management. Experience with IPC and serialisation technologies such as FlatBuffers, Unix-domain sockets or named pipes. Experience with CMake, automated testing and CI/CD pipelines. Experience with cross-compilation, ideally for aarch64 platforms. Strong experience with unit testing, code coverage and quality gates. Comfortable working within formal engineering processes, including peer review, traceable changes and documented design decisions. Experience working on safety-critical, mission-critical or highly regulated software. Desirable Skills & Experience Experience developing medical devices or other safety-critical systems. Knowledge of IEC 62304, ISO 13485 or similar regulated software development standards. Experience with medical alarm systems or other alarm and fault-management systems. Understanding of IEC 60601-1-8 or equivalent safety standards. Experience working with state-machine-driven supervisors and fault-management systems. Experience with NVIDIA Jetson, CUDA or GPU-accelerated processing. Experience with Yocto and embedded Linux board-support packages. Experience with systemd, sd_notify, D-Bus and journald. Experience with OpenSSL, TensorRT or similar external technologies. Experience using Docker for development environments. Experience with GoogleTest, behaviour-driven testing or Gherkin. Python experience for tooling and deployment scripts. Experience contributing to software FMEA activities and implementing risk controls. Engineering Environment You'll be working with technologies and practices including: C++17 Embedded Linux NVIDIA Jetson / aarch64 Yocto CMake & Conan Docker GoogleTest FlatBuffers Boost.Asio D-Bus systemd / sd_notify Unix-domain sockets NVMe storage SonarQube MISRA C++ 2023 Doxygen CI/CD and target-hardware testing Equal Opportunities AND Digital is an equal opportunity employer. We welcome applications from people of all backgrounds and experiences and are committed to creating an inclusive workplace where everyone can thrive. We will make reasonable adjustments throughout the recruitment process where required. AI Statement We champion tech that helps people work smarter, but we want to get to know you! If you use AI to assist with your application or interview prep, please ensure all information submitted remains an accurate, truthful representation of your personal achievements and capabilities rather than generating false or misleading information. We may reject applications where AI is used inappropriately at any stage of the recruitment process.