Lightweight, private, and customizable retrieval-augmented chatbot running entirely on your Mac.

Based on the excellent work by pruthvirajcyn and his Medium article.

This is my personal implementation of a local RAG (Retrieval-Augmented Generation) chatbot using:

• Ollama for running open-source LLMs and embedding models locally.
• Streamlit for a clean and interactive chat UI.
• ChromaDB for storing and querying vector embeddings.

As of 2025年07月17日, I'm using:

• 🔍 Embedding model: nomic-embed-text-v2-moe
• 🧠 LLM: gemma3n

• 🔒 Privacy: No data is sent to the cloud. Upload and query your documents entirely offline.
• 💸 Cost-effective: No API tokens or cloud GPU costs. You only pay electricity.
• 📚 Better than summarizing: With long PDFs or multiple documents, even summaries may not contain the context you need. A RAG chatbot can drill deeper and provide contextual answers.

✅ Recommended: At least 16GB of RAM on your Mac. Preferably 24GB+ for smoother experience.

git clone https://github.com/eplt/RAG_Ollama_Mac.git
cd RAG_Ollama_Mac

python3 -m venv venv
source venv/bin/activate

pip install -r ./src/requirements.txt

ollama serve
ollama pull gemma3n
ollama pull toshk0/nomic-embed-text-v2-moe:Q6_K

Place your .pdf files in the data/ directory.

python ./src/load_docs.py

To reset and reload the vector database:

python ./src/load_docs.py --reset

streamlit run ./src/UI.py

Ask questions and the chatbot will respond using relevant context retrieved from your documents.

• ✏️ Modify Prompts
  Update prompt templates in UI.py to guide the chatbot’s tone or behavior.

• 🔄 Try Different Models
  Ollama supports various LLMs and embedding models. Run ollama list to see what’s available or try pulling new ones.

• ⚙️ Tune Retrieval Parameters
  Adjust chunk size, overlaps, or top-K retrieval values in load_docs.py for improved performance.

• 🚀 Extend the Interface
  Add features like file upload, chat history, user authentication, or export options using Streamlit’s powerful features.

• Ollama not running?
  Make sure ollama serve is active in a terminal tab.

• Missing models?
  Run ollama list to verify models are downloaded correctly.

• Dependency issues?
  Double-check your Python version (3.7+) and re-create the virtual environment.

• Streamlit errors?
  Ensure you're running the app from the correct path and activate your virtual environment.

• Planning to support non-PDF formats (Markdown, .txt, maybe HTML).
• Will experiment with additional LLMs like phi-3, mistral, and llama3.
• Might integrate chat history persistence and better document management.

Local RAG is now more accessible than ever. With powerful small models and tools like Ollama, anyone can build a private, intelligent assistant — no cloud needed.

If you found this useful or have ideas to improve it, feel free to open a PR or drop a star ⭐️