Modern software engineering teams depend on a fragmented set of tools to manage planning, development, version control, collaboration, and monitoring activities. While each tool is effective individually, the lack of seamless integration among them results in fragmented workflows, limited visibility, and increased operational complexity. This paper presents DevSync OS — Unified Engineering Lifecycle Orchestrator, a centralized web based platform designed to integrate and streamline the complete software development lifecycle SDLC into a single cohesive environment. The system connects project lifecycle management, GitHub repository activity, workflow visualization, and team collaboration through a unified operational interface. Built on the MERN stack MongoDB, Express.js, React.js, Node.js , DevSync OS integrates with GitHub via the Octokit API for real time repository synchronization. Workflow and system architecture visualization are powered by React Flow and Mermaid.js. The system implements role based access control RBAC through JSON Web Tokens JWT to ensure secure, structured access across Administrator, Project Manager, and Developer roles. Test results demonstrate API response times under 200ms, 100 database uptime during load testing, and stability for up to 20 concurrent simulated users. DevSync OS successfully reduces context switching, improves transparency, and increases team coordination, offering a scalable solution aligned with modern Agile and DevOps engineering practices. Engineering Lifecycle Management MERN Stack GitHub Integration Workflow Visualization Role Based Access Control DevOps Agile Software Development. 74-81 Smart Innovations in Computer Science and Applications Special Issue Vrushali P. Ghaywankar