Nexus: AI-Powered Second Brain for Personal Knowledge Management

Abstract

The proliferation of digital information across heterogeneous platforms has intensified cognitive overload and fragmented personal knowledge management. This paper presents Nexus, a web-based Second Brain application designed to centralize the capture, organization, and intelligent retrieval of multi-format digital resources including notes, web links, documents, and social media content. The system employs the MERN stack architecture integrated with semantic search, personalized tagging, and AI-driven content categorization to deliver a unified knowledge management experience. Being a cloud-hosted web application, Nexus is inherently accessible across multiple devices through any standard web browser, with all content centrally stored and managed using MongoDB. Cross-device synchronization is implemented through cloud APIs and event-driven mechanisms to ensure real-time accessibility. A NoSQL document-oriented storage model using MongoDB supports scalable and low-latency data operations across structured and unstructured content types. Experimental evaluation demonstrates improved retrieval precision and reduced organizational fragmentation in comparison with conventional knowledge management tools such as Notion and Evernote. The intuitive dashboard and knowledge- map visualization further support long-term retention and contextual content discovery. Nexus establishes a scalable framework for personal knowledge engineering with prospective extensions toward generative AI integration, collaborative knowledge mapping, and cross-platform mobile deployment.