Modernize App with React and .Net Core

Job Description We are looking for an experienced full-stack developer or development team to modernize an existing application using React for the frontend and .NET Core for the backend. The current application is functional but needs improvements in architecture, performance, user experience, security, and maintainability. The selected developer will review the existing system, recommend a modernization approach, and rebuild or migrate the application in phases. Key Responsibilities * Review the existing application, codebase, database, and integrations * Migrate or rebuild the frontend using React * Modernize backend services using .NET Core and REST APIs * Improve application performance, security, and scalability * Create a responsive and user-friendly interface * Refactor legacy code and remove unnecessary dependencies * Integrate existing third-party services and APIs * Implement proper authentication and authorization * Maintain existing business logic and application functionality * Perform unit, integration, and regression testing * Support deployment and production release * Prepare technical documentation and knowledge-transfer materials Required Skills * Strong experience with React, JavaScript, TypeScript, HTML, and CSS * Strong experience with .NET Core, C#, Web API, and Entity Framework * Experience modernizing legacy applications * Knowledge of SQL Server or PostgreSQL * Experience with REST APIs and third-party integrations * Understanding of secure coding practices and application architecture * Experience with Git, CI/CD, and cloud deployment * Good communication and documentation skills Preferred Experience * Azure cloud services * Microservices or modular application architecture * Authentication using JWT, OAuth, or SSO * Performance optimization and security testing * Experience working with e-commerce, ordering, CRM, CMS, or enterprise applications Expected Deliverables * Existing application and architecture assessment * Modernization and migration plan * React-based frontend * .NET Core backend APIs * Updated database integrations * Tested and production-ready application * Deployment support * Source code and technical documentation Application Requirements Please include: * Relevant React and .NET Core projects * Examples of legacy application modernization work * Your proposed approach for reviewing and migrating the application * Estimated team structure and availability * Expected timeline and cost model * Any questions or assumptions regarding the project Candidates should be comfortable working with an existing system and delivering the modernization in structured phases without disrupting current business operations.