Freelance Senior .NET Developer / Tech Lead

Project/Client: Fintech Location: Lithuania **Start Date:**ASAP Duration: 12 months **Language:**English Role Overview: We’re looking for a Senior .NET Developer / Tech Lead to join our engineering team and build payment-focused backend solutions in a regulated fintech environment. This is a hands-on role combining software development with technical leadership. You’ll design and develop backend services, contribute to technical and architectural decisions, and help the team maintain high engineering standards. Key Responsibilities: Design and develop backend services using C# / modern .NET Contribute to technical design and architectural decisions Build integrations with REST APIs, third-party platforms, messaging, and file-based interfaces Ensure code quality through code reviews and engineering best practices Mentor developers and lead technical discussions Work with SQL, relational databases, CI/CD, and Docker Build secure, reliable, and scalable software solutions Collaborate with product, compliance, QA, and other engineering teams Must-Have Requirements: 7+ years of hands-on C# / .NET experience Strong backend development experience Experience with REST APIs, integrations, and distributed systems Strong SQL and relational database experience Experience with Docker and CI/CD Understanding of secure and reliable software development Experience as a Senior Engineer, Tech Lead, or similar Ability to take technical ownership and guide other developers Nice to Have: Experien