Senior Data Backend Engineer

Description

European Union **Work type:** Office/Remote **Technical Level:** Senior **Job Category:** Software Development 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.