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