Our client Orange Tree Systems is looking for DotNet Developer / VB.net in Lahore.  As a .NET Engineer, you will lead the design and delivery of scalable, secure, and high-performance backend systems powering web, desktop mobile, and multi-platform applications. In this role, we are specifically looking for a developer with strong VB.NET experience, as a key part of the work involves migrating an existing project written in VB.NET. What You'll Do Backend Engineering - Design, build, test, and maintain backend services and REST/GraphQL APIs using .NET (ASP.NET Core). - Work on the migration of legacy VB.NET applications into modern C# .NET Core architecture. - Analyze, refactor, and modernize existing code while preserving business logic and system stability. - Implement secure authentication and authorization using OAuth2, OpenID Connect, JWT, and industry-standard identity providers. - Integrate internal services and third-party systems with a focus on security, resilience, performance, and data integrity. Quality, Collaboration & Operations - Apply engineering best practices including clean architecture, testing, documentation, and performance optimization. - Participate in code reviews, design discussions, and architectural decision-making. - Troubleshoot production incidents, perform root-cause analysis, and implement long-term fixes. - Collaborate cross-functionally to deliver business-critical features with high reliability. Background & Qualifications - 7+ years of backend engineering experience with strong depth in .NET. - Strong hands-on experience with VB.NET and proven experience working on migration or modernization projects. - Expert proficiency in C#, ASP.NET Core, and API design (REST; GraphQL is a plus). - Strong experience in SQL Server/PostgreSQL, including schema design and performance tuning. - Hands-on experience with Azure cloud services and cloud-native development. - Understanding of microservices, event-driven architecture, distributed systems, and reliability principles. - Experience with CI/CD, version control, and automated testing. - Docker/Kubernetes experience is a plus. - Healthcare domain experience (e.g., EHR/EMR, HL7, FHIR, pharmacy or healthcare platforms) is a strong advantage. Technology Stack - Backend: .NET / ASP.NET Core (Web API, MVC), microservices - Legacy / Migration Focus: VB.NET to C# .NET Core - Frontend Exposure: React, Angular, Blazor - Databases: SQL Server, PostgreSQL, Cosmos DB - DevOps: Docker, Kubernetes, CI/CD - Architecture: Microservices, event-driven systems, distributed services What We're Looking For - Migration-Focused Developer: Comfortable working with legacy VB.NET systems and modernizing them into scalable .NET Core solutions. - System Thinker: Designs secure, scalable systems with strong engineering fundamentals. - Strong Ownership: Drives delivery end-to-end and raises the quality bar. - Collaborative Builder: Communicates clearly and works effectively across teams. - Quality Focused: Writes clean, testable, maintainable code and improves existing systems. - Adaptable: Learns quickly and applies modern tools, patterns, and cloud services. Why Join Orange Tree Systems - Build healthcare technology that creates real-world impact - Work with a fast-growing, highly skilled engineering team - Deep exposure to Azure, scalable backend systems, modernization initiatives, and modern DevOps practices - Opportunity to shape architecture, performance, and long-term platform direction - Play a key role in the transformation of a legacy healthcare pharmacy platform into a modern engineering ecosystem