🤖 Gemini-Powered Chatbot (LangChain + Streamlit)

🧠 A basic AI chatbot built using LangChain and Google Gemini
⚡ Features real-time streaming responses and session-based memory
🧩 Clean separation between UI and LLM logic

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📁 Project Structure

.
├── app.py                  # Streamlit UI
├── chatbot_stremlit.py     # LangChain + Gemini logic
├── requirements.txt
├── .gitignore
├── README.md
└── .env                    # API keys (created by user)

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🌟 Key Features

• 🧠 Session-based Conversational Memory
  Maintains chat history using st.session_state

• ⚡ Streaming Responses
  Uses LangChain .stream() for live output

• 🧩 Clean Architecture

  • chatbot_stremlit.py → AI logic
  • app.py → UI and interaction

• 🔐 Secure API Management
  Uses .env file with python-dotenv

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🛠️ Tech Stack

• Language: Python 3.10+
• LLM: Google Gemini (gemini-2.5-flash-lite)
• Frameworks: LangChain (LCEL), Streamlit
• Utilities: python-dotenv

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🚀 Complete Setup Guide

1️⃣ Clone the Repository

git clone https://github.com/DevDoshi19/ChatBot_using_Basic_LangChain.git

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2️⃣ (Optional) Create Virtual Environment

python -m venv venv
source venv/bin/activate      # macOS / Linux
venv\Scripts\activate         # Windows

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3️⃣ Install Dependencies

pip install -r requirements.txt

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4️⃣ Create .env File

Create a file named .env in the root directory.

GOOGLE_API_KEY=your_google_gemini_api_key_here

⚠️ Never commit .env to GitHub.

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5️⃣ Run the App

streamlit run app.py

The chatbot will open in your browser.

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🧠 How It Works (High-Level)

User → Streamlit UI → LangChain Prompt
     → Gemini Model → Streamed Response

• Chat history is injected using MessagesPlaceholder
• Responses stream live using st.write_stream
• Memory persists within the session

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📦 requirements.txt (Example)

streamlit
langchain
langchain-google-genai
python-dotenv

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🧠 What I Learned

• Using LangChain Expression Language (LCEL)
• Handling Streamlit reruns via Session State
• Implementing real-time LLM streaming
• Structuring AI apps cleanly and scalably

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👨‍💻 Author

Dev Doshi B.Tech | AI / ML | LangChain | Streamlit | Generative AI

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🔗 Let’s Connect

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🚀 Demo

chatbot_langchain.-.Made.with.Clipchamp.mp4

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Thank you for reading