Principle Engineer - Backend

Job Description

Are you interested in joining Europe’s fastest growing companies? Do you want to impact the wellbeing of millions of employees?

If yes, then keep reading and join us to make an impact in a fast-paced and dynamic environment where you’ll play a key role in boosting everyday wellbeing, at home, at work. Everywhere!

Epassi’s purpose is to boost everyday well-being. We are a leading provider of employee benefit solutions across Europe. We were established in Finland in 2007, and in 2008 we were the first company to launch a mobile-payable employee benefit payment solution in Europe. Since then, we have consistently grown, diversifying our products and introducing our services into new markets.

Epassi has been awarded by the Financial Times as one of the fastest-growing companies in Europe on multiple occasions.

We are currently hiring a Principal Engineer (Backend) to work across all Epassi brands and markets, to be based in the UK, Netherlands, Germany, Finland, Sweden, or Spain – Remote (work from home), with regular travel to visit engineering teams across Europe.

Your mission at Epassi

As our Principal Engineer (Backend), you will be the most senior backend individual contributor in the engineering organisation, working across all Epassi brands and markets spanning multiple European countries. Reporting directly to the VP of Engineering, you will set the technical direction for our backend systems as we build and scale the Epassi ONE platform — a shared platform powering multiple brands across numerous domains with complex regulatory requirements across different markets. We are building this platform with an AI-first development approach, and you will be instrumental in defining what that means in practice — establishing how our engineers use AI tools to write, review, test, and ship production code faster and at higher quality.

You will work closely alongside our other Principal Engineers focused on web and mobile, forming a senior technical leadership cohort that drives architectural coherence across the full stack. Together, you will operate at the intersection of deep technical expertise and organisational influence, driving the decisions that affect every product squad, mentoring senior engineers across teams, and ensuring our Java/Spring Boot platform is built to scale.

This is not a management role — it’s a hands-on technical leadership position where your code, designs, and architectural judgement directly shape the future of Epassi’s technology.

Your responsibilities will be:

• Define and evolve the backend architecture for the Epassi ONE platform, establishing the technical patterns, conventions, and reference implementations that all engineering teams follow.
• Own cross-cutting architectural decisions across all brands and markets, ensuring consistency, scalability, and regulatory compliance in a multi-country platform.
• Lead the design of complex backend systems including microservices architecture, API strategy, data modelling, and integration patterns across the Java/Spring Boot ecosystem.
• Serve as the go-to technical authority for backend engineering, providing hands-on guidance on the most challenging technical problems across any team or domain.
• Write production code using AI-assisted development tools and workflows, conduct architecture reviews, and create technical specifications — leading by example and demonstrating how AI-first practices accelerate delivery without compromising quality.
• Champion and define Epassi’s AI-first engineering practices — establishing guidelines, prompt patterns, and workflows for how engineers leverage AI tools (e.g., Claude, Copilot) for code generation, code review, testing, documentation, and architectural exploration.
• Collaborate closely with the Principal Engineers for web and mobile to ensure architectural coherence across the full stack — aligning on API contracts, shared patterns, and cross-platform technical decisions.
• Drive the technical strategy for platform growth, defining how services, APIs, and data models support multiple brands and markets through configuration rather than separate applications.
• Partner directly with the VP of Engineering, CTO, and Heads of Engineering to translate business strategy into technical roadmaps and investment priorities.
• Mentor and elevate senior and staff engineers across all teams, raising the technical bar organisation-wide through code reviews, design sessions, and technical coaching — including coaching engineers on effective AI-assisted development techniques.
• Establish and champion engineering best practices including API governance, service reliability standards, observability, testing strategies, and CI/CD practices.
• Evaluate and recommend technology choices, frameworks, AI tooling, and developer productivity improvements that improve system performance and operational excellence.
• Identify and lead high-impact cross-team technical initiatives such as performance improvements, platform scaling, or infrastructure modernisation.
• Represent Epassi’s engineering organisation externally through technical talks, blog posts, open-source contributions, or community engagement.

You’ll be successful in this role if you:

• Establish a clear, well-documented backend architecture and technical strategy within your first 6 months that is adopted across all engineering teams.
• Directly unblock and accelerate the most critical cross-team technical initiatives, measurably reducing time-to-delivery for key platform milestones.
• Raise the engineering bar organisation-wide — evidenced by improved code quality, fewer production incidents, and consistent adoption of architectural standards.
• Drive measurable adoption of AI-first development practices across the engineering organisation, with clear improvements in developer velocity, code quality, and time-to-production.
• Build strong trust with Engineering Managers, Heads of Engineering, and fellow Principal Engineers across all brands, becoming the first person teams consult on complex backend decisions.
• Contribute production-quality code and technical designs that serve as reference implementations for the wider engineering organisation.
• Successfully mentor at least 2–3 senior engineers toward staff-level impact within your first 18 months.
• Proactively identify and address systemic technical risks before they become delivery blockers — bringing solutions, not just problems.
• Drive measurable improvements in platform reliability, API performance, and developer experience.

What you’ll be doing (daily):

• Writing and reviewing code across the most complex and impactful parts of the backend platform, using AI-assisted development tools as a core part of your workflow.
• Leading architecture design sessions and RFC reviews for cross-cutting technical decisions.
• Pairing with engineers across different teams and brands to solve their hardest backend problems — including coaching them on effective AI-assisted coding techniques.
• Working with the web and mobile Principal Engineers on cross-stack architectural decisions, API contracts, and shared platform patterns.
• Collaborating with the VP of Engineering on technical strategy, investment priorities, and organisational technical health.
• Reviewing and shaping API contracts, data models, and service boundaries for platform services.
• Conducting deep-dive technical investigations into system performance, reliability, and scalability concerns.
• Mentoring senior and staff engineers through design reviews, code walkthroughs, and 1:1 technical coaching.
• Experimenting with and evaluating new AI development tools, establishing best practices, and sharing findings across the engineering organisation.
• Documenting architectural decisions, technical standards, and reference patterns for the engineering organisation.
• Contributing to hiring by conducting technical interviews and calibrating the engineering hiring bar for senior roles.

What you should bring:

• 12+ years of software engineering experience with deep, hands-on backend expertise.
• Extensive experience with Java and the JVM ecosystem, including Spring Boot, and a strong track record of building production systems at scale.
• Demonstrated ability to write production-quality code using AI-assisted development tools (e.g., Claude, Copilot, Cursor) — you should already be using these tools daily and have a clear point of view on how they change the way engineers work.
• Proven experience designing and evolving large-scale microservices architectures, including API design, event-driven systems, and distributed data management.
• Deep expertise in cloud infrastructure (AWS, GCP, or Azure), containerisation, and modern CI/CD and DevOps practices.
• Strong understanding of relational and non-relational databases, data modelling, and performance optimisation.
• Experience working in multi-product or multi-brand environments where platform consistency across diverse regulatory or business requirements is essential.
• Track record of influencing technical direction across an organisation of 100+ engineers without direct management authority.
• Exceptional ability to communicate complex technical concepts clearly to both engineering and non-technical leadership audiences.
• Experience building shared platforms or services that support multiple products, brands, or markets at scale.
• Strong opinions, loosely held — you bring conviction to technical debates but stay open to better ideas.

Nice to have:

• Experience in fintech, employee benefits, or regulated industries across multiple European jurisdictions.
• Contributions to open-source projects or public technical writing.
• Experience with event sourcing, CQRS, or saga patterns in distributed systems.
• Familiarity with React.js or React Native — not as a primary skill, but enough to collaborate effectively with the web and mobile Principal Engineers and their teams.
• Experience defining AI-assisted development standards or rolling out AI tooling across an engineering organisation.

Your track record:

• Technical Vision: You see the big picture and the small details. You can define a multi-year backend architecture strategy and then write the first service that proves it works.
• AI-First Mindset: You don’t just use AI tools — you’ve fundamentally changed how you write software because of them. You understand where AI accelerates engineering and where human judgement remains critical, and you can teach an entire organisation to work this way.
• Influence Without Authority: You shape how an entire engineering organisation builds software — not through hierarchy, but through the quality of your ideas, your code, and your ability to bring people along.
• Hands-On Leadership: You lead from the codebase, not the sidelines. You write production code, review pull requests, and stay deeply connected to the technical reality of the systems you architect.
• Cross-Stack Partnership: You work as part of a senior technical leadership cohort. You collaborate naturally with Principal Engineers in web and mobile, finding the right boundaries between backend and frontend concerns and making joint decisions that serve the whole platform.
• Organisational Impact: You think beyond your immediate scope. You identify systemic problems, propose cross-team solutions, and drive them to completion across organisational boundaries.
• Mentoring at Scale: You multiply your impact by raising the capabilities of senior engineers around you, helping them grow into staff and principal-level contributors.
• Communication: You translate between deep technical detail and business strategy fluently, ensuring alignment between engineering execution and company objectives.
• Pragmatism: You know when to build for the future and when to ship for today. You make trade-offs transparently and help the organisation make informed technical bets.

Why You Should Join Us

• Be part of an ambitious growth journey and join a global community of driven, bold, entrepreneurial, yet humble Epassians in a company that is constantly evolving.
• Work with a clear purpose — boosting everyday wellbeing — and create a meaningful, positive impact on both individuals and society.
• Thrive in an open and inclusive culture with low hierarchy, where relationships are built on respect, camaraderie, and shared successes and challenges.
• Come as you are — we’ll bring out the best in you and support your personal and professional growth.
• Join a fast-growing tech company with a strong financial foundation, offering opportunities to grow and make an impact together with us.
• Benefit from an inspiring and supportive work environment where employee wellbeing is a true priority.
• Contribute to solidifying our position as the number one player in Europe’s employee benefit market and help shape the next wave of success.

The hiring manager for this position is Awn Ali, VP of Engineering at Epassi. For more information, contact the Talent Acquisition team on careers@epassi.com