State-of-the-art commercial conversational models are typically limited to public data, lacking direct access to personal or specialized documents due to security concerns about exposing sensitive information. To bridge this gap, the Hybrid Documents RAG based Chatbot empowers users to securely tap into their own document collections for personalized information retrieval. By seamlessly combining rapid local indexing, context- sensitive ranking, and reranking, the system enables fast, precise searches without relying on cloud-based services. This privacy- centric design ensures that sensitive data remains safely on- device, while also offering online mode for accessing more compu- tational power. Ultimately, the chatbot offers a groundbreaking paradigm in personalized information discovery, striking an ideal balance between performance, flexibility, and security.

• Hybrid Retrieval – Supports both online (web search) and offline (local document search) for flexibility and privacy.
• Efficient Document Processing – Extracts text from PDFs, DOCX, and other formats using semantic and fixed-size chunking for better context.
• Vector-Based Search – Uses FAISS and embeddings for fast and accurate information retrieval.
• Reranking for Accuracy – Combines BM25, cross-encoders, and hybrid retrieval to improve search relevance.
• Adaptive AI Models – SLMs for speed, LLMs for complex queries, with dynamic selection based on query needs.
• Interactive Conversational Search – Refines responses with follow-up queries and learns from user feedback.
• Privacy & Security – Offline mode ensures sensitives data stays on-device, reducing cloud dependencies.
• User-Friendly Interface – Enables seamless document search with conversational interaction.

This chatbot enhances document-based search with AI-driven conversation, accuracy, and privacy.

1. Install Ollama:

   • Download and install Ollama from ollama.com.
   • Install required models (e.g., qwen2.5:0.5b, nomic-embed-text):

     ollama pull qwen2.5:0.5b
     ollama pull nomic-embed-text

2. MongoDB Setup:

   • Install MongoDB Compass and create a database named rag_app_db with a collection sessions.

• From the main directory run following command

python main.py

This will start Frontend, Backend, MongoDb and Ollama.

• Maharun Afroz
• Sanjida Amin Nadia
• Tasnia Hossain
• Tahmina Mozumdar