LangChain

LangChain is a Python framework for building agents and LLM-powered applications. It provides interoperable components and third-party integrations to simplify AI application development while maintaining flexibility as the technology evolves.

Key Features

• Model interoperability — Swap between different LLM providers (OpenAI, Anthropic, etc.) through standardized interfaces
• Rich integrations — Connect to vector stores, tools, retrievers, and external data sources
• Agent orchestration — Build complex workflows with LangGraph for controllable agent behavior
• Real-time data augmentation — Easily connect LLMs to diverse internal and external systems
• Modular architecture — Component-based design for rapid prototyping and iteration

Installation

pip install langchain
# or with uv
uv add langchain

Basic Usage

from langchain.chat_models import init_chat_model

# Initialize a chat model
model = init_chat_model("openai:gpt-4")

# Send a message
result = model.invoke("Hello, world!")
print(result)

Notable Details

• License: MIT
• Language: Python
• Community: 130K+ GitHub stars with active open-source ecosystem
• Ecosystem: Integrates with LangGraph (agent orchestration), LangSmith (observability), and Deep Agents (complex task handling)