Senior Data Backend Engineer

N-iX is looking for a Senior Data Backend Engineer (Kotlin) to join a new engagement with a leading European fintech company. This is an exciting opportunity to become part of a modern engineering organization that is redefining how businesses manage corporate spending through innovative financial technology solutions. The company is building an AI-native engineering environment where developers leverage cutting-edge AI tools throughout the software development lifecycle. You'll work within cross-functional product squads, contributing to both existing platforms and new product initiatives while helping shape scalable, data-driven backend services. Responsibilities: • Design and develop scalable backend services using Kotlin. • Build and own clean API layers serving both internal and customer-facing products. • Work at the intersection of backend engineering and data platforms, integrating analytical data into product experiences. • Develop solutions leveraging BigQuery and OLAP serving layers. • Collaborate closely with cross-functional engineering teams in an agile environment. • Apply AI-assisted development practices using modern engineering tools. • Contribute to high-quality, maintainable, and scalable software architecture. Requirements: • Strong commercial experience with Kotlin. • Hands-on experience with BigQuery in production environments. • Experience working with OLAP serving layers and analytical query systems. • Solid background in backend architecture and API design. • Experience building production-grade distributed systems. • Strong understanding of modern software engineering best practices. • Professional level of English. • Currently based in the European Union. Nice to have: • Java experience. • PostgreSQL. • AWS and/or GCP. • Experience with REST and/or gRPC APIs. • Familiarity with AI-assisted development tools such as GitHub Copilot or Claude Code. We offer*: • Flexible working format - remote, office-based or flexible • A competitive salary and good compensation package • Personalized career growth • Professional development tools (mentorship program, tech talks and trainings, centers of excellence, and more) • Active tech communities with regular knowledge sharing • Education reimbursement • Memorable anniversary presents • Corporate events and team buildings • Other location-specific benefits *not applicable for freelancers