Senior .NET Engineer

📍 Kraków, Poland (Hybrid) We are looking for a Senior Backend Software Engineer to help build and scale a modern cloud-native SaaS platform used by customers globally. In this role, you will work on high-availability backend systems, distributed services, and scalable APIs powering customer-facing applications. You’ll collaborate closely with international engineering teams, product managers, and frontend developers to deliver reliable, secure, and high-performing solutions in a fast-paced agile environment. This is an opportunity to join a modern product-focused engineering environment where backend architecture, scalability, and engineering quality are highly valued. Responsibilities Design, develop, and maintain scalable backend services using C# and .NET 6+ Build and optimise RESTful APIs for modern web applications Contribute to the evolution of a microservices-based architecture focused on scalability and resilience Develop cloud-native solutions leveraging AWS services Ensure systems are secure, highly available, and performant Collaborate with frontend engineers to support seamless API integrations Partner with product and design teams to translate business requirements into technical solutions Participate in architecture discussions, technical planning, and code reviews Write clean, maintainable, and well-tested code following engineering best practices Implement and improve automated testing strategies including unit and integration testing Identify and reduce technical debt while improving long-term system sustainability Monitor application performance and contribute to reliability and observability improvements Support CI/CD and deployment processes within an agile development environment Stay up to date with emerging technologies and contribute to continuous improvement initiatives. Required Qualifications 5+ years of experience in backend software engineering within product, SaaS, or web environments Strong proficiency in C#, .NET, and ASP.NET Core Experience designing and building scalable web applications and REST APIs Solid understanding of distributed systems and cloud-native architecture principles Hands-on experience with AWS or similar cloud platforms Experience working with microservices and event-driven architectures Strong knowledge of relational databases such as SQL Server Experience with ORM frameworks such as Entity Framework Understanding of software design patterns and clean architecture principles Experience working in agile development teams Strong communication and collaboration skills. Nice to Have Experience with AWS services such as Lambda, API Gateway, DynamoDB, or Elasticsearch Familiarity with Infrastructure as Code tools such as Terraform Experience with CI/CD pipelines and automation tools Knowledge of Docker and Kubernetes Exposure to serverless architectures Experience supporting backend systems for React-based frontend applications Familiarity with observability and monitoring tools Experience working in distributed international teams. What We Offer Opportunity to work on modern cloud-native products and large-scale distributed systems Collaborative international engineering environment Flexible hybrid working model in Kraków Career growth opportunities and continuous learning support Exposure to modern technologies, architecture, and engineering practices Competitive compensation and benefits package Supportive team culture focused on innovation and technical excellence.