AI Agent Frameworks

Frameworks and libraries for building autonomous AI agents, multi-agent systems, and tool-using LLM applications.

Quick Comparison

Tool	Pricing	Open Source	Self-Hosted	Maturity
AutoGen	open-source	Yes	Yes	maintenance
CrewAI	freemium	Yes	Yes	growing
LangGraph	open-source	Yes	Yes	established
LlamaIndex Workflows	open-source	Yes	Yes	established
OpenAI Agents SDK	open-source	Yes	Yes	growing
Pydantic AI	open-source	Yes	Yes	growing
Semantic Kernel	open-source	Yes	Yes	established
smolagents	open-source	Yes	Yes	growing

AutoGen

Microsoft's multi-agent framework (succeeded by Microsoft Agent Framework)

Open Source open-source Free Tier

Multi-agent conversations Code generation agents Research and experimentation

CrewAI

Framework for orchestrating role-playing AI agents

Open Source freemium Free Tier

Multi-agent workflows Role-based agent teams Sequential and parallel task execution

LangGraph

Stateful, controllable agent orchestration by the LangChain team

Open Source open-source Free Tier

Complex agent control flow Stateful multi-step agents Human-in-the-loop workflows

LlamaIndex Workflows

Event-driven agent orchestration from the LlamaIndex team

Open Source open-source Free Tier

RAG-powered agents Data-aware agent workflows Event-driven orchestration

OpenAI Agents SDK

OpenAI's lightweight SDK for building agentic workflows

Open Source open-source Free Tier

Simple agentic loops Tool-use agents Handoff patterns between agents

Pydantic AI

Type-safe agent framework from the creators of Pydantic

Open Source open-source Free Tier

Type-safe agent development Structured output extraction MCP and A2A integration

Semantic Kernel

Microsoft's enterprise SDK for AI orchestration

Open Source open-source Free Tier

Enterprise AI integration .NET and Java ecosystems Azure-native workflows

smolagents

Hugging Face's minimalist library for code-writing agents

Open Source open-source Free Tier

Code-writing agents Hugging Face ecosystem integration Lightweight agent prototyping