Principal Software Architect at Appvia in London, England, GB

Principal Software Architect - UK Security Clearance eligibility required.

Location: London, UK - Hybrid (~1-2 days per month 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 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 Architect, you will be the architectural voice within our software engineering engagements: owning solution design, shaping technical direction, and constructively challenging both the business and technical architecture of the systems we help modernise.

Domain Driven Design sits at the heart of how we approach this. You will lead the domain modelling that underpins our solutions, working with customer stakeholders and domain experts to build a shared understanding of the business, establish a ubiquitous language, and translate that into well-defined bounded contexts, service boundaries, and system decomposition. Where a customer's existing architecture doesn't reflect their domain, you'll make the case for change and lead it.

This is a hands-on role. You'll spend most of your time developing alongside the team, but you'll be doing so while driving the solution: ensuring the domain model is expressed faithfully in the code, making and documenting architectural decisions, and ensuring what we build is coherent, evolvable, and aligned to the customer's business goals, not just well-engineered in isolation.

You will work closely with delivery managers, platform engineers, customer architects, and senior stakeholders to influence decisions that sit above the codebase: system decomposition, integration strategy, domain modelling, and the trade-offs between business need and technical direction. You'll also help lead and grow the team, and contribute to Appvia's broader engineering strategy by shaping the architectural patterns, DDD practices, standards, and AI-assisted engineering approaches we apply consistently across customer engagements.

Interview Process - 3 Stage

1. Discovery conversation with Talent Acquisition
2. Technical & Architecture Interview with the Engineering Team
3. 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

About You

You are an architecturally minded senior engineer: someone who thinks in domains, systems, and trade-offs, but who has never stopped coding. You believe that good architecture starts with a deep understanding of the business domain, and you're energised by shaping the why and what of a solution as much as the how. You're comfortable challenging established thinking with customers in a consulting environment, earning influence through credibility, clarity, and delivery.

You'll bring:

• Deep, practical experience applying Domain Driven Design on real systems: strategic design (bounded contexts, context mapping, ubiquitous language) as well as tactical patterns (aggregates, domain events, anti-corruption layers) and knowing when each is warranted.
• Experience leading collaborative domain discovery with business stakeholders, using techniques such as Event Storming, domain storytelling, or similar.
• Strong architectural judgement, with a track record of owning and driving solution design on complex systems, not just contributing to it.
• Proven delivery of microservice-based architectures where service boundaries were derived from the domain, including the hard parts: data ownership, integration patterns, and evolving boundaries as understanding of the domain deepens.
• The ability to understand a customer's business architecture, connect it to technical decisions, and constructively challenge it when it doesn't serve the outcome.
• Confidence communicating and defending architectural decisions to senior stakeholders, and documenting them clearly (e.g. ADRs, C4 or similar).
• Strong hands-on full-stack development skills. You lead from within the codebase.
• 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 growing domain-driven and architectural thinking across a team.
• 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

• Own the architecture and solution design of modern, scalable software systems across customer engagements.
• Lead domain discovery and modelling with customers, establishing bounded contexts, a ubiquitous language, and a shared understanding between business and engineering.
• Shape and challenge business and technical architecture: service boundaries, domain models, dependencies, and integration strategy across complex systems.
• Ensure the domain model is reflected in the software itself, keeping code, architecture, and business understanding aligned as systems evolve.
• Act as a trusted architectural advisor to customers, guiding decision-making, articulating trade-offs, and influencing direction at a senior level.
• Work hands-on across the stack, particularly on React-based applications. Architecture at Appvia is done in the code, not just on the whiteboard.
• Establish and document architectural decisions, patterns, and standards that outlive individual engagements.
• Drive improvements in development processes, testing strategy, and delivery cadence.
• Support teams in reducing technical debt and improving long-term maintainability and evolvability.
• Collaborate with platform and cloud engineers to deliver cohesive end-to-end solutions.
• Mentor engineers and grow DDD and architectural capability within Appvia's engineering practice.

Technical Skills

Core technologies (in order of importance):

• Java / Spring
• NoSQL / SQL databases
• TypeScript / JavaScript
• HTML / CSS / XML
• Playwright
• Docker / Kubernetes
• Maven
• GitLab
• AWS

Nice to have:

• GovUK UI Framework
• Azure / GCP
• .NET

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.