Shape how safety-critical software is verified at the highest level. We're partnering with a growing, highly respected engineering SME specialising in safety-critical embedded systems. They are looking for a Principal Software Engineer to play a key role in developing and assuring high-integrity embedded software, including a safety-certified real-time operating system. This is a hands-on software engineering role within the verification team, combining technical leadership with deep involvement in verification, validation, and certification activities. The Role You'll operate as a senior technical authority while remaining close to the code. Responsibilities include: Leading verification strategy and approach for embedded software systems Designing, developing, and maintaining test frameworks, tools, and automation Performing low-level software verification across multiple architectures Contributing directly to code-level activities (primarily C / embedded environments) Driving verification activities across the full software lifecycle Supporting certification to standards such as IEC 61508, DO-178C, ISO 26262 Mentoring engineers and setting best practices within the verification team Working closely with customers to provide technical guidance and support What We're Looking For Essential: Degree in Engineering, Computer Science, Maths or similar Experience with Real-Time Operating Systems (e.g. FreeRTOS, SafeRTOS or similar) Strong background in embedded software engineering (C) Significant experience in software verification / validation Experience developing test tools, frameworks, or automation Understanding of low-level / hardware-near software behaviour Experience working in a controlled or safety-critical environment Degree in Engineering, Computer Science, Maths or similar Strong communication skills and ability to engage with stakeholders Highly Desirable: Knowledge of safety standards ( IEC 61508, DO-178C, ISO 26262, IEC 62304 ) Experience with ARM architectures (Cortex M / A) or similar Understanding of debugging at processor level Knowledge of software lifecycle, requirements, and configuration management Exposure to networking, multicore systems, or embedded security Working Environment Bristol-based Hybrid working (minimum 3 days onsite; more during onboarding) Collaborative, engineering-led environment with strong technical depth Package & Benefits Competitive salary with annual review Performance-related bonus Generous pension contribution Private healthcare, income protection & life assurance 25 days holiday (increasing with service) Flexible working hours Ongoing professional development and training