CollabCore is presented as an all-in-one, web-based platform that replaces the patchwork of separate task boards, chat apps, and issue trackers typically used by small- and mid-size development teams, thus eliminating costly context-switching and duplicate administration. The system is engineered on a clean three-tier architecture—React 18 + Tailwind + Redux on the client, Spring Boot 3 REST APIs on the server, and a normalized MySQL schema underneath—secured end-to-end with stateless JWT tokens. Core modules include a Kanban-style board for issues, project-scoped real-time chat, and an email-driven invitation workflow, all tied together so that discussion, tasks, and membership stay in one context. A rich domain model linking users, projects, issues, comments, and chat messages underpins agile workflows while preserving traceability and access control. Academically, the thesis evidences full-stack engineering competence from requirements capture through deployment; practically, it delivers a production-ready tool that the author’s peer teams can adopt immediately. The conclusion demonstrates that open-source technologies, when carefully layered and integrated, can provide enterprise-grade collaboration capabilities without the overhead of enterprise-scale budgets.