5 principal software test engineer jobs found in London, greater london

Internal Title: Senior Full Stack Developer Location: London, UK (Hybrid - typically 1-2 days per month in office) Contract: Permanent, Full-time OR Outside IR35 Contract, 6 months with view to extend Day Rate (contract): £500-550 per day Package (perm): £70,000 - £80,000 + 10% Bonus + 10% Shares + Benefits (see more below) About Appvia Appvia is a specialist cloud, platform, and solutions engineering consultancy, helping organisations modernise software systems, improve developer productivity, and adopt cloud-native practices that enable long-term, sustainable delivery. Our software engineering capability focuses on modern application development, domain-driven design, and improving delivery outcomes through better architecture, testing, and developer experience. We work across complex, high-impact environments in both the public and private sector, delivering solutions where quality, scalability, and reliability are critical. About The Role We're hiring...

This role is delivered within secure environments. Candidates must be eligible for UK SC and DV clearance and hold UK Citizenship. Opening: Join the Mission At ByDesign Secure, we believe that world-class security shouldn't be an afterthought—it should be the foundation. We are an independent, outputs-based consultancy dedicated to solving the most complex data assurance challenges in the UK public sector. Currently, we are working on a landmark transformation of a cross-government secure IT system. This is an exciting opportunity to help architect a private cloud environment from the ground up and modernize the end-user services that power national decision-making. We don't believe in ʺbilling by the hourʺ or rigid hierarchies; we are a lean, expert team focused on delivering high-impact technical outcomes. If you are a self-starter who thrives on autonomy and wants to see your engineering or architectural decisions shape the future of sovereign security, we want to talk to...

Lead Backend Software Engineer – Data Services Federated Data Services | Distributed Systems | Apache Spark | DataFusion | Python | Kubernetes Location: London (2 days per week onsite) Rate: £700–£800 per day (Outside IR35) Duration: Initial 6-month contract with likely extension Overview We're looking for an experienced Lead Backend Software Engineer to join a high-profile programme building secure, cloud-native data services that will support data-driven research and innovation at national scale. This is a founding engineering role, offering the opportunity to shape the architecture, engineering standards, and core data services from the ground up. Working closely with the Engineering Manager and a small team of senior engineers, you'll establish the technical foundations for a complex federated data platform operating within a highly regulated environment. We're looking for someone who enjoys building from first principles, thrives in ambiguity, and...

Lead Backend Software Engineer - Data Services Federated Data Services | Distributed Systems | Apache Spark | DataFusion | Python | Kubernetes Location: London (2 days per week onsite) Rate: £700-£800 per day (Outside IR35) Duration: Initial 6-month contract with likely extension Overview We're looking for an experienced Lead Backend Software Engineer to join a high-profile programme building secure, cloud-native data services that will support data-driven research and innovation at national scale. This is a founding engineering role, offering the opportunity to shape the architecture, engineering standards, and core data services from the ground up. Working closely with the Engineering Manager and a small team of senior engineers, you'll establish the technical foundations for a complex federated data platform operating within a highly regulated environment. We're looking for someone who enjoys building from first principles, thrives in ambiguity, and can balance...

Lead Backend Software Engineer - Data Services Federated Data Services | Distributed Systems | Apache Spark | DataFusion | Python | Kubernetes Location: London (2 days per week onsite) Rate: £700 - £800 per day (Outside IR35) Duration: Initial 6-month contract with likely extension Overview We 're looking for an experienced Lead Backend Software Engineer to join a high-profile programme building secure, cloud-native data services that will support data-driven research and innovation at national scale. This is a founding engineering role, offering the opportunity to shape the architecture, engineering standards, and core data services from the ground up. Working closely with the Engineering Manager and a small team of senior engineers, you 'll establish the technical foundations for a complex federated data platform operating within a highly regulated environment. We 're looking for someone who enjoys building from first principles, thrives in...