Senior Software Test Engineer (Python & Embedded Systems) in London

Salary: Up to £75,000 per annum, depending on experience

Location: Predominantly remote, with occasional visits to Farnborough

Security Requirements: Sole UK National | Eligible for SC Clearance, with the ability to progress to DV Clearance

Are you looking for a better work-life balance without leaving the defence sector behind? If you have experience on defence or national security programmes and want greater flexibility with less time spent on-site, this could be the opportunity you're looking for.

We're seeking a Senior Software Test Engineer with a strong background in embedded software and firmware testing to help ensure the quality, reliability and performance of complex device-based systems. This is a senior, hands-on position where you'll shape test strategy while remaining involved in automation, integration testing and fault investigation.

You’ll work on challenging non-deterministic systems, designing robust test approaches where software behaviour can vary based on system state, environmental conditions and external inputs. You’ll also take ownership of Python-based automation frameworks, driving quality standards and continuous improvement across the engineering team.

This is an excellent opportunity to join a highly skilled team, solve complex technical challenges and influence the testing approach for cutting-edge embedded systems within a secure defence environment.

What You’ll Be Doing

• Lead the testing strategy for complex embedded software and firmware products.
• Design, develop and maintain Python-based automated test frameworks.
• Create robust test approaches for non-deterministic systems, validating behaviour where outputs may vary based on environmental conditions, system state or external inputs.
• Design test cases for complex and uncertain scenarios, ensuring system resilience under real-world operating conditions.
• Perform software, firmware, integration and system-level testing across hardware and software environments.
• Analyse intermittent, non-repeatable and unexpected behaviours to identify root causes.
• Collaborate closely with Embedded Software Engineers throughout the software development lifecycle.
• Support firmware releases, deployments, upgrades and regression testing activities.
• Drive continuous improvement across testing processes, tooling and automation capability.
• Mentor engineers and promote best practice in software quality and test design.
• Contribute to CI/CD pipelines and quality gates for software delivery.

Essential Skills & Experience

• Significant experience testing embedded software systems and firmware.
• Strong understanding of the embedded software development lifecycle.
• Experience working on defence, aerospace, government, national security or other highly regulated engineering programmes.
• Understanding of hardware/software integration challenges and system-level testing.
• Experience testing products that interact with physical devices, sensors, communications equipment or embedded platforms.
• Extensive experience designing and executing test strategies for complex software systems.
• Strong background in test design, exploratory testing and risk-based testing techniques.
• Experience testing non-deterministic systems, artificial intelligence-enabled systems, autonomous platforms or software where outcomes are not always predictable.
• Ability to analyse ambiguous test results and develop meaningful validation approaches.
• Experience of manual, automated, integration, system and regression testing.
• Strong Python development skills with proven experience building and maintaining automated test frameworks.
• Experience integrating automated testing into CI/CD environments.
• Knowledge of modern test automation tools and methodologies.
• Experience creating reusable, scalable and maintainable automation solutions.
• Knowledge of firmware deployment, upgrades and version management.
• Experience working with Linux-based environments.
• Understanding of software quality metrics, defect management and release processes.
• Strong troubleshooting and root-cause analysis skills.

Security Requirements

Due to the nature of the work, applicants must:

• Be a sole UK national.
• Be eligible and willing to obtain Security Check (SC) Clearance.
• Be capable of obtaining Developed Vetting (DV) Clearance in the future if required.
• Have the unrestricted right to work in the UK without needing sponsorship.

Benefits

• Salary up to £75,000 depending on experience.
• Performance-related bonus.
• Private healthcare.
• Enhanced pension contribution.
• Ongoing professional development and training.
• Predominantly remote working.