AI Agents in Python in 2026: LangChain (143k Stars) vs CrewAI vs AutoGen - Build Your First Agent Today

LangChain (143,470 stars), CrewAI (56,644) and Microsoft AutoGen (60,241) are the three big Python agent frameworks - here is a plain comparison plus a working first agent in 20 lines.

💡 What You Will Learn

LangChain (143,470 stars), CrewAI (56,644) and Microsoft AutoGen (60,241) are the three big Python agent frameworks - here is a plain comparison plus a working first agent in 20 lines.

## The short answer **LangChain** (143,470 stars, MIT) is the Swiss-army ecosystem: chains, tools, memory, RAG, and agent loops with every model provider. **CrewAI** (56,644 stars, MIT) makes multi-agent teams easy - role-play agents that delegate to each other. **AutoGen** (60,241 stars, MIT) from Microsoft is the research-grade framework for complex multi-agent conversations and code execution. ## Your first agent in 20 lines (LangChain) ```bash pip install langchain langchain-openai ``` ```python from langchain.agents import create_react_agent, AgentExecutor from langchain_openai import ChatOpenAI from langchain.tools import tool @tool def add(a: int, b: int) -> int: """Add two numbers.""" return a + b llm = ChatOpenAI(model="gpt-4o-mini") agent = create_react_agent(llm, [add], llm.bind_tools([add])) executor = AgentExecutor(agent=agent, tools=[add]) print(executor.invoke({"input": "What is 12345 + 67890?"})) ``` ## Framework comparison | Framework | Stars | Strength | Best for | |:----------|------:|:---------|:---------| | LangChain | 143,470 | Ecosystem, RAG, tools | Production apps | | CrewAI | 56,644 | Multi-agent teams | Role-based workflows | | AutoGen | 60,241 | Complex conversations, code exec | Research, multi-agent | ## Real numbers - LangChain powers a large share of production RAG/agent apps and integrates 700+ providers. - CrewAI's abstractions (Agent, Task, Crew) cut boilerplate dramatically - a 3-agent pipeline is ~100 lines. - All three run with local Ollama (177,825 stars) models at $0 inference cost. ## FAQ **Q: Which should I learn first?** A: LangChain - biggest community, most tutorials, and the concepts transfer to the others. **Q: Do I need a GPU?** A: No - agents just call an LLM API; use local Ollama or any cloud model. **Q: Are agents reliable?** A: Single agents with clear tools are reliable; multi-agent systems need careful prompt design and error handling.