Developer frameworks and SDKs for building autonomous AI agents with tool use, planning, multi-step reasoning, and orchestration capabilities.
24 tools compared · Layer 3 · Updated April 29, 2026
Ranked by community traction, recent activity, and breadth of capabilities. Tap any tool for full pros, cons, pricing, and alternatives.
OpenClaw is an open-source personal AI assistant developed by Austrian developer Peter Steinberger. First published in November 2025 as Clawdbot and renamed to OpenClaw in late January 2026, it became the fastest-growing open-source project in GitHub history — surging from 9,000 to 60,000+ stars in days, then blowing past 347,000 stars by April 2026.
+Most-starred repo in GitHub history — 347K+ stars
LangChain is the most widely adopted framework for building LLM-powered applications and AI agents, founded in 2022 by Harrison Chase. The company provides an open-source Python and TypeScript framework with abstractions for chains, agents, tools, memory, and retrieval that make it easy to compose complex AI systems.
+Largest ecosystem and community in AI application development
AutoGPT is the pioneering autonomous AI agent platform — the project that introduced the world to recursive AI agents in early 2023 and was, for a time, the fastest-growing open-source project in GitHub's history. As of April 2026 it sits at 183,000+ stars, making it one of the four most-starred AI agent frameworks on GitHub.
+Pioneer of the autonomous AI agent space — unmatched brand recognition
LangGraph is LangChain's graph-based orchestration framework for building stateful, multi-step AI agents. Unlike linear chains, LangGraph models agent workflows as directed graphs with nodes (functions or LLM calls) and edges (conditional routing), enabling cycles, branching, parallel execution, and durable state across long-running interactions.
+Most production-ready open-source agent framework in 2026
Strands Agents is an open-source AI agent SDK developed by AWS that takes a model-driven approach to building and running AI agents in just a few lines of code. Launched as a preview in May 2025, Strands reached version 1.0 in July 2025, bringing production-ready multi-agent orchestration capabilities. The framework uses the reasoning abilities of modern LLMs to handle planning and tool usage autonomously, eliminating the need for hardcoding complex task flows.
+Production-proven by AWS teams (Amazon Q, AWS Glue)
The OpenAI Agents SDK is a lightweight Python framework for building multi-agent workflows with built-in tracing and guardrails. It provides primitives for defining agents with instructions and tools, orchestrating handoffs between agents, and implementing input/output guardrails for safety.
Llama Stack is Meta's standardized API and SDK for building AI applications on top of Llama models. It provides a unified interface for inference, safety, memory, and agentic workflows — with swappable providers for local, cloud, and on-device deployment. As the official framework for the Llama ecosystem, it is becoming the default for teams building on open-source Llama models.
CrewAI is a framework for orchestrating multi-agent AI systems where specialized agents collaborate to complete complex tasks. It provides abstractions for defining agent roles, goals, tools, and workflows, enabling teams of AI agents to work together like a human crew. CrewAI supports sequential, parallel, and hierarchical task execution patterns and integrates with all major LLM providers.
AutoGen is Microsoft's open-source framework for building multi-agent AI systems. It enables the creation of conversational agents that can work together, use tools, and interact with humans to solve complex tasks. AutoGen supports customizable agent behaviors, flexible conversation patterns, and integrations with various LLMs. The framework is popular for building research assistants, coding agents, and automated analysis pipelines.
Google's Agent Development Kit (ADK) is a modular framework for building AI agents that integrates natively with Gemini models and Vertex AI. It supports multi-agent architectures, tool use, memory, and deployment to Google Cloud, providing an end-to-end solution for building agents in the Google ecosystem.
The Vercel AI SDK is a TypeScript toolkit for building AI-powered web applications with React, Next.js, and other frameworks. It provides streaming UI components, structured generation, tool calling, and multi-step agent workflows. The SDK supports all major LLM providers through a unified interface and is the most popular choice for frontend developers building AI features into web applications.
Dify is an open-source platform for building LLM applications with both visual and code-based interfaces. It provides a workflow orchestration engine, RAG pipeline builder, agent framework, and model management—all accessible through a web UI. Dify supports 50+ LLM providers, offers enterprise features like SSO and access control, and can be self-hosted or used as a cloud service.
DSPy is a framework from Stanford for programming—not prompting—foundation models. It replaces manual prompt engineering with composable, optimizable modules. DSPy compilers automatically tune prompts and weights for your specific pipeline and dataset, enabling more reliable LLM applications.
Semantic Kernel is Microsoft's enterprise SDK for integrating AI into applications. It provides planners for multi-step task execution, plugin architectures for tool use, memory systems, and connectors for all major LLM providers. Available in C#, Python, and Java, Semantic Kernel is designed for enterprise .NET shops building AI-powered features into existing applications.
Pydantic AI is a Python agent framework from the creators of Pydantic, leveraging type hints for type-safe AI agents with structured output validation, automatic self-correction, and tight Pydantic Logfire integration for tracing. 16.5K+ GitHub stars, free and open-source.
Instructor is a popular open-source library for getting structured outputs from LLMs using Pydantic models.
Hermes Agent is Nous Research's open-source autonomous AI agent with persistent memory across sessions. Released February 2026; hit 95.6K GitHub stars in seven weeks. Memory persists in ~/.hermes/memories/ plus 8 external provider plugins (Mem0, Honcho, OpenViking, etc.). Self-creates skills that compound over months of use.
Agno (formerly Phidata) is an open-source Python framework for building production-grade AI agents and multi-agent systems. 39K+ GitHub stars, 23+ LLM providers supported, 100+ pre-built tool integrations, MCP-compatible. Includes AgentOS — a stateless FastAPI runtime — and a control plane UI for monitoring.
Atomic Agents is an open-source agent framework built on top of Instructor, designed for building AI agents with a focus on structured outputs and composability. It extends Instructor's structured output capabilities into a full agentic framework with tool use, multi-step planning, and agent orchestration, emphasizing type-safe, schema-driven agent development.
Smolagents is Hugging Face minimalist agent framework for building AI agents with code-based actions.
21st.dev is the largest React component registry for the agentic internet — an open-source, community-driven marketplace of shadcn/ui-based React + Tailwind components, blocks, and hooks. 1.4M developers (200K MAU), pivoting into a full agent deployment SDK.
Vercel for background agents — hosting and deployment platform for long-running AI agents with sandboxed compute, scheduling, and message streaming.
Mastra is a TypeScript-first agent framework for building production AI applications. It provides primitives for agents, workflows, RAG, integrations, and memory with a focus on developer experience and type safety. Mastra is designed for full-stack TypeScript developers who want to build AI features without leaving their existing tech stack.