Principal Software Engineer - UK Security Clearance eligibility required. Location: London, UK (Hybrid ~1 day per week in office / onsite) Contract: Permanent, Full-time Package: £80,000-100,000 10% bonus 10% shares options benefits About Appvia At Appvia, we help organisations modernise how they build and operate software. We are a specialist cloud, platform, and solutions engineering consultancy, delivering resilient, scalable systems that enable teams to move faster while maintaining quality, security, and reliability. Our work spans cloud platforms, developer experience, and modern application delivery. We partner with customers across public and private sectors to reduce technical debt, improve engineering practices, and support long-term system evolution using modern software engineering approaches. About the Role As a Principal Software Engineer, you will play a senior technical leadership role across Appvia’s software delivery engagements. You will help customers and lead a team to design, build, and evolve modern software systems, while guiding teams towards best practices in architecture, testing, and developer productivity. This is a hands-on leadership role for an experienced engineer who enjoys operating across design, architecture, and delivery. You will work closely with engineers, delivery leads, and platform teams, shaping technical direction, supporting early-stage solution design, and mentoring teams delivering complex software systems. You will also contribute to Appvia’s broader engineering capability, influencing standards, patterns, and approaches that are applied consistently across customer engagements. Interview Process - 4 Stage Discovery conversation with Talent Acquisition Technical assessment Technical conversation Competency-focused final interview Requirements About You You are a senior software engineer with strong architectural judgement and a passion for well-designed systems. You are comfortable leading technically, influencing delivery decisions, and working closely with customers in a consulting environment. You’ll bring: Strong experience with Domain Driven Design (DDD) and modern system decomposition. Proven delivery of microservice-based architectures. Deep hands-on experience with React and full-stack development. Experience improving engineering effectiveness through testing strategy, automation, and developer tooling. Exposure to AI-assisted development approaches to improve code quality and productivity. Confidence mentoring engineers and leading technical discussions. A consulting mindset, able to translate business problems into practical technical solutions. Experience in regulated or public sector environments is beneficial but not required. Responsibilities Lead the design and delivery of modern, scalable software systems. Shape architecture, service boundaries, and dependencies across complex systems. Drive improvements in development processes, testing strategy, and delivery cadence. Work hands-on across the stack, particularly on React-based applications. Support teams in reducing technical debt and improving long-term maintainability. Collaborate with platform and cloud engineers to deliver cohesive end-to-end solutions. Act as a senior technical advisor to customers, guiding decision-making and trade-offs. Contribute to shared engineering standards, patterns, and best practices within Appvia Technical Skills Core technologies (in order of importance): Java / Spring NoSQL / SQL databases React / Javascript HTML / CSS / XML Playwright Docker / Kubernetes Maven GitLab AWS Nice to have: GovUK UI Framework Azure / GCP .NET Benefits Why join Appvia? We are a self-funded, London based startup; providing businesses with a fast and secure way to deploy containerised applications into the cloud. We are on a mission to enable organisations to make cloud-based software delivery simple and efficient, whilst having the insights into costs, security and cadence. As a company that holds customers at the heart of everything we do, we are looking for candidates that want to make a real change to how Dev and Ops is working in the industry. With us our customers, like the UK’s Home Office & Bank of England, are harnessing cloud-native technologies, limiting the challenges of infrastructure management and rapidly delivering digital products. What’s on offer? ⚖️ Work-life balance Flexible working with core hours of 10-4pm because we know life happens outside of work Hybrid working - only one compulsory office day per month 25 days’ holiday a year, plus bank holidays An additional day off for your birthday Enhanced maternity and paternity to full pay Workplace Nursery Benefit to help working parents For your well-being Full Private Healthcare cover for you with partners and children covered 50% Death in Service Cycle to Work scheme Electric Car Scheme Pension plus a salary sacrifice option for even greater savings Employee Assistance Programme Free hygiene products available in the London office Mental health support Free therapy through AXA Access to the Headspace App Trained Mental Health First Aiders Other fun perks Learning budget of £1,000 a year Your own MacBook Pro while you work at Appvia Dog friendly office Wear what makes you comfortable Free snacks in the office Pool table & ping pong table Regular team socials, board game nights, industry meetups and more! But don’t just take our word for it, you can check out what our Appvians say about us on Glassdoor and by following us on LinkedIn, Twitter and TikTok. We are proud to be an equal opportunities employer and actively encourage, respect, and recognise diversity of thought and background throughout the business. All applicants will be considered for employment without attention to age, ethnicity, religion, sex, sexual orientation, gender identity, family or parental status, national origin, or veteran, neurodiversity, and disability status. Note: While all roles are active and approved at the time of posting, the dynamic nature of our start-up means some applications may be processed to pipeline talent for future opportunities rather than current openings. We will strive to keep you informed of any changes to the status of your application.