Built a cybersecurity intelligence platform combining a RAG chatbot and an interactive STIX visualization workspace. Developed responsive React.js interfaces for document upload, chatbot interaction, evidence tracing, and threat graph exploration. Implemented backend REST APIs and CRUD-style workflows for document ingestion, chunking, retrieval, STIX parsing, and AI querying. Integrated source-grounded LLM question answering for cyber threat intelligence analysis. Supported PDF, HTML, text, pasted reports, and STIX JSON ingestion workflows.