Senior Backend Engineer (Product)

Finom; Warszawa; On-site; PLN 270,000 - 370,000; Full time

Job summary

Finom is looking for a Senior Backend Engineer who thinks like a product builder, thrives in a cross-functional environment, and is passionate about scalable financial infrastructure. You’ll contribute to a domain team delivering value to hundreds of thousands of European businesses.

You’ll own the why behind what you build, collaborate with product managers and frontend/mobile engineers, and mentor teammates while improving processes.

Qualifications

• Proficient in .NET/C# with experience designing distributed systems.
• Ability to communicate clearly with technical and non-technical audiences.
• Strong product mindset and collaboration across disciplines.

Responsibilities

• Architect and evolve backend services in a cross-functional team.
• Collaborate with product managers, frontend and mobile engineers.
• Mentor teammates and improve development processes.

Skills

.NET

C#

Distributed systems

English communication

Product mindset

Tools

PostgreSQL

Redis

RabbitMQ

Kafka

Kubernetes

GCP

Job description

• We’re looking for a Senior Backend Engineer who thinks like a product builder, thrives in a collaborative, cross-functional environment, and is passionate about creating robust, scalable financial infrastructure. You’ll be part of a domain team where various engineering crafts (Backend, Frontend, Mobile, ML/AI engineers, and QA) work together to own and evolve a shared product area that delivers real value to hundreds of thousands of businesses across Europe
• You’re pragmatic, learn quickly, and have a proven track record of shipping products that matter. You communicate clearly across disciplines and genuinely enjoy the dynamics of a cross-functional team where everyone contributes to solving the same customer problems. Above all, you’re curious – about the product, the users, the business, and how your technical decisions impact all three
• As a product-minded backend engineer, you don’t just implement tickets. You understand the “why” behind what you’re building, challenge assumptions when needed, and proactively identify opportunities to create better outcomes. You’re comfortable discussing trade-offs with product managers, explaining technical constraints to business stakeholders, and collaborating with frontend and mobile engineers to design elegant end-to-end solutions
• You have deep expertise in .NET and C# with a strong appreciation for maintainable, scalable code, and distributed architectures. But more importantly, you know when to apply that expertise and when simpler solutions serve the product better. You’ve built data-intensive applications before and understand the concepts of working in a regulated environment
• You take ownership not just of your code, but of the outcomes. You move without being prompted, whether that’s jumping into a customer issue, improving team processes, or mentoring colleagues. You’re curious about adjacent domains – you might peek at the frontend code, ask questions about the ML models, or dive into analytics to understand how features perform
• Quality is non-negotiable for you. Automated testing, thorough code reviews, and security best practices are fundamental to how you work. You balance technical excellence with pragmatism, always keeping the end user and business goals in mind
• Backend: .NET/C#, PostgreSQL, Redis, RabbitMQ, Kafka, Kubernetes, GCP
• You’ll work alongside teams using React (Web), Swift (iOS) / Kotlin (Android), Python/ML frameworks, and modern test automation tools (Playwright, Appium)

Hands-on experience architecting and evolving distributed systems in productionClear, concise communication in English across technical and non-technical audiencesStrong business acumen – you understand how your work connects to company objectivesAt least 5 years of professional backend development with a product engineering mindsetExcellent knowledge of .NET platform and C#A builder’s mentality: you care deeply about shipping great products, not just writing great codeProven ability to collaborate effectively with product managers, designers, and engineers from other disciplines