Best Open-source AI Agent Frameworks tools

Mastra

TypeScript framework for building scalable AI agents and workflows

Microsoft Agent Framework

Unified framework for building, orchestrating, and deploying AI agents

CrewAI

Lightning‑fast Python framework for autonomous multi‑agent automation

Agno

Fast, private, scalable framework for building multi-agent AI systems

Composio

Unified SDKs to empower AI agents with real‑world tools

Kortix

Build, manage, and train autonomous AI agents with Kortix

LangGraph

Orchestrate resilient, stateful language agents with graph‑based workflows

Pydantic AI

Build type-safe, observable GenAI agents the FastAPI way

VoltAgent

TypeScript framework for production-ready AI agents with observability

Atomic Agents

Build modular AI agents with predictable, reusable components.

Letta

Build stateful AI agents with persistent, self‑editing memory

smolagents

Run sandboxed code agents with minimal code and any LLM

Claude Code Plugins

Modular AI agents and plugins for end-to-end software development

PraisonAI

Build, coordinate, and run multi‑AI agents with low‑code simplicity

AutoGen

Build autonomous multi-agent AI applications with a flexible framework

Pocket Flow

Build AI apps with a 100‑line, dependency‑free framework

SuperAGI

Easily build, manage, and run autonomous AI agents