🧠 PDF RAG Chatbot with Free LLM + ChromaDB

A Streamlit-based chatbot that lets you query PDF files using Retrieval-Augmented Generation (RAG) with ChromaDB and free HuggingFace LLMs.

🚀 Features

• Upload any resume PDF 📄
• Parses and chunks documents using LangChain
• Uses ParentDocumentRetriever for hierarchical chunking
• Embeds using sentence-transformers
• Stores vectors locally with ChromaDB
• Answers powered by Hugging Face's Mixtral-8x7B-Instruct endpoint
• Returns answers with source snippets ✨

🧩 Tech Stack

• 🖥 Streamlit – UI for chat interface
• 🧠 LangChain – for RAG logic and document parsing
• 🔍 ChromaDB – local vector store
• 🧩 Sentence-Transformers – text embeddings
• 🤖 Mixtral-8x7B-Instruct – HuggingFace-hosted LLM (free tier)

🛠 Setup

# 1. Clone repo
git clone https://github.com/<your-username>/pdf-rag-chatbot.git
cd pdf-rag-chatbot

# 2. Setup virtual environment
python3 -m venv venv
source venv/bin/activate  # or venv\Scripts\activate on Windows

# 3. Install dependencies
pip install -r requirements.txt

# 4. Add your HuggingFace token to `.env`
HUGGINGFACEHUB_API_TOKEN=your_token_here

# 5. Run the app
streamlit run app.py