Principal Software Engineer - UK Security Clearance eligibility required.

Principal Software Engineer - UK Security Clearance eligibility required.

Location: London, UK (Hybrid ~1 day per week in office / onsite)

Contract: Permanent, Full-time

Package: £80,000-90,000 + 10% bonus + 10% shares options + benefits About Appvia

At Appvia, we help organisations modernise how they build and operate software. We are a specialist platform engineering, software, and AI enablement consultancy, delivering resilient, scalable systems that help teams move faster while maintaining quality, security, and reliability.

Our work spans cloud platforms, developer experience, modern application delivery, and AI-assisted engineering practices. We partner with customers across public and private sectors to reduce technical debt, improve engineering standards, and evolve complex systems using modern software engineering approaches.

Since the start of 2026, our Software Engineering practice has grown rapidly into a dedicated team supporting large-scale modernisation programmes across public and private sectors, and we’re continuing to invest heavily in growing the capability further. About the Role

As a Principal Software Engineer, you will play a hands-on technical leadership role across Appvia’s software engineering engagements, helping lead the design, delivery, and evolution of modern software systems.

You will work closely with delivery managers, platform engineers, and customer stakeholders to drive high-quality outcomes across complex software modernisation programmes. You'll help lead and grow the team and contribute to Appvia’s broader engineering strategy by influencing tooling, development standards, AI-assisted engineering approaches, testing practices, and architectural patterns used consistently across customer engagements. Interview Process - 3 Stage

• Discovery conversation with Talent Acquisition
• Technical Interview with Engineering Team
• Final Interview with Leadership

Important

You must be eligible for UK Security Clearance (SC) :

• British Passport or ILR
• Resided in the UK for the last 5 years
• No criminal record or financial irregularities

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 consultancy, growing rapidly while staying true to what got us here: a human, engineering-led culture built on trust, ownership, and getting things done.

As we scale, we’re maturing as a business and expanding into new areas across platform engineering, software, data, and AI. We’re intentional about keeping our culture at the heart of it. We operate with a flat structure, agile ways of working, and a strong focus on collaboration, where good ideas come from anywhere and people are trusted to make an impact.

We work alongside our customers to solve complex, real-world problems: modernising systems, improving delivery, and building scalable platforms that enable long-term success.

If you want to be part of a team that values people as much as technology and gives you the space to grow while working on meaningful challenges, Appvia is the place to do it. What’s on offer?

• Work-life balance
• Flexible working hours - because we know life happens outside of work
• Hybrid working - outcomes focused working
• 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.