DocMind AI – Backend

Backend service for DocMind AI, an AI-powered document assistant that lets users chat with one or multiple PDF documents using Retrieval-Augmented Generation (RAG).

Built with FastAPI, LangChain, Google Gemini, ChromaDB, and SQLAlchemy.

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✨ Features

• 📄 Upload and process PDF documents
• 💬 AI-powered conversational chat
• 📚 Multi-document RAG (chat across multiple PDFs)
• 🔍 Source citations with page numbers
• 📝 AI-generated document summaries
• ⚡ Streaming responses (Server-Sent Events)
• 💡 Suggested follow-up questions
• 🧠 Conversational history with question rewriting
• 📂 Session management
• 📌 Pin and organize chat sessions

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🛠 Tech Stack

• FastAPI
• LangChain
• Google Gemini
• ChromaDB
• SQLAlchemy
• SQLite
• PyMuPDF
• Server-Sent Events (Streaming)

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📁 Project Structure

app/
├── api/
├── services/
├── models/
├── repositories/
├── prompts/
├── utils/
└── ...

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🚀 Getting Started

Clone the repository

git clone https://github.com/<your-username>/docmind-ai-backend.git

cd docmind-ai-backend

Create a virtual environment

python -m venv .venv

Activate it.

Windows

.venv\Scripts\activate

Linux / macOS

source .venv/bin/activate

Install dependencies

pip install -r requirements.txt

Configure environment variables

Create a .env file.

GOOGLE_API_KEY=your_google_api_key

Run the server

uvicorn app.main:app --reload

The API will be available at

http://localhost:8000

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📡 Main API Endpoints

Method	Endpoint	Description
POST	/upload	Upload a PDF
POST	/chat/stream	Stream AI responses
POST	/summarize	Generate document summary
GET	/documents	List uploaded PDFs
DELETE	/documents	Delete a PDF
GET	/sessions	Get chat sessions
POST	/sessions	Create a session
PATCH	/sessions/{id}/pin	Pin/Unpin session
GET	/source	View source page

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🏗 Architecture

React Frontend
        │
        ▼
FastAPI API
        │
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LangChain
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Google Gemini
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ChromaDB Vector Store
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PDF Documents

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🎯 Highlights

• Streaming AI responses
• Multi-document semantic retrieval
• Context-aware conversations
• Source-grounded answers
• Modular service architecture
• Responsive frontend integration

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📄 License

This project is created for learning and portfolio purposes.

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👨‍💻 Author

Omkar Parab

If you found this project interesting, feel free to connect or explore the frontend repository.