Best AI Agent Frameworks

Open-source frameworks for building LLM applications and AI agents: tool use, retrieval, memory and multi-agent orchestration. LangChain has the largest ecosystem of integrations, LlamaIndex is the strongest for connecting agents to your own documents and data, and CrewAI makes role-based multi-agent teams easy to set up. AutoGen from Microsoft focuses on conversational multi-agent systems, DSPy replaces hand-written prompts with optimised, programmatic pipelines, and deepset's Haystack stack targets production search and RAG. Read our guide to what changed in AI agent frameworks on the blog.