Principal Engineer - Backend

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 tool