Design, develop, and maintain scalable backend services using .NET (C#). Build and maintain RESTful APIs consumed by PHP Laravel applications and other internal services. Design, optimize, and maintain SQL database schemas, queries, and stored procedures. Ensure performance, reliability, security, and scalability of backend systems. Integrate third-party services and internal systems via APIs. Participate in architecture discussions, technical decision-making, and code reviews. Troubleshoot, debug, and optimize existing applications and databases. Collaborate with frontend developers, product managers, and other stakeholders to deliver features end-to-end. Mentor junior and mid-level developers and promote best engineering practices. Contribute to improving development workflows, tooling, and system observability.