What is LangChain?
LangChain provides modular building blocks for LLM applications — chains, agents, memory, retrieval, and tool use. It's the most widely adopted framework for building AI apps in Python and JavaScript. If you're building anything beyond a simple API call to an LLM, LangChain likely has a component for it.
Quick start
1
pip install langchain langchain-openai 2
from langchain_openai import ChatOpenAI 3
llm = ChatOpenAI(model="gpt-4o")
4
response = llm.invoke("Explain RAG in one paragraph")
Use cases
→RAG applications
→Multi-step AI agents
→Document Q&A systems
→LLM application backends
Compatible models
Works with every major LLM provider
Why this matters for India
// india context
Most AI startup job descriptions in India mention LangChain. Learning it is a career investment.