Our client is an established FinTech software provider with over 19 years of experience, supporting financial institutions across Europe, Asia, and other global markets. With a team of specialists across three continents and part of a billion-dollar technology group, the company develops secure and scalable banking platforms used by regulated financial institutions worldwide. As a Senior .NET Software Engineer, you will design and develop mission-critical financial systems powering digital banking and payment solutions used by international clients. Responsibilities: Design and implement backend systems and platform components using C# / .NET / .NET Core; Analyze business requirements and translate them into robust system architecture and technical solutions. Develop and maintain high-performance APIs and backend services; Ensure data integrity, system reliability, and high-availability performance; Write, test, debug, and maintain complex software components; Produce technical documentation, including system specifications and API documentation; Ensure software complies with industry security standards (including OWASP); Participate in code reviews and engineering best practices; Provide guidance and technical leadership to other developers; Collaborate with product, architecture, and client teams across the full software development lifecycle. Requirements: BSc or MSc in Computer Science or a related field; 4+ years of professional experience in .NET / C# software development; Strong knowledge of .NET Core and modern backend architectures; Experience developing mission-critical or high-availability systems; Strong experience with relational databases and SQL; Deep understanding of software design patterns; Experience working with Git and CI/CD tools (DevOps, Jenkins, Bamboo); Strong knowledge of EU regulations, including DORA and GDPR; Strong problem-solving and debugging skills; Excellent communication and collaboration abilities; Fluent written and spoken English. Nice to Have Experience developing banking or payment systems; Knowledge of financial or accounting terminology; Experience with OAuth2 / OpenID Connect identity systems; Experience with Azure cloud environments; Experience with Docker or containerized deployments; Familiarity with Agile development (Scrum / Kanban). The Employer Offers A senior-level engineering role with real ownership and technical influence; Competitive salary aligned with experience and European FinTech benchmarks; Annual performance review and bonus system; Monthly salary: 4,6005,100 gross + performance bonuses Additional private health insurance after 6 months; 21 vacation days per year and free parking in Vilnius office; Opportunity to travel internationally (including Cyprus team visits); Long-term growth opportunities as the platform and team expand; Collaborative, professional team working on complex, real-world challenges.