Agent frameworks
Open source
Browser Use
Browser Use lets an agent operate a real browser. The open-source library is Python, and the cloud SDK supports Python and TypeScript.
- browser
- Python
- TypeScript
Open sourcebrowser-use.com
Best frameworks for building agents
These are the agent frameworks and nearby building blocks listed on AgentAtlas. Most are open source libraries. Dify and Flowise are visual builders you can host. Hugging Face is a hub for models and demos, not an agent library.
Microsoft's own listings say new agent projects should use Microsoft Agent Framework. AutoGen is in maintenance mode, and Semantic Kernel remains published with that same pointer.
How to choose
Choose the language first. Python libraries include LangChain, LangGraph, LlamaIndex, CrewAI, Haystack, PydanticAI, and the OpenAI Agents SDK. TypeScript listings are Mastra, the Vercel AI SDK, and Agent-Native. Google ADK ships in more than one language. Use Dify or Flowise when you want a visual editor instead of a library. Use Ollama when the missing piece is a model running on your own computer, and Composio when the agent needs signed-in access to other apps.
Python libraries
Libraries for prompts, retrieval, tools, and multi-agent flows. CrewAI's listing notes a paid cloud on top of the open source framework.
Agent frameworks
Open sourceCrewAI
CrewAI lets you define agents with roles and tasks that they work through together. The framework is open source, with a paid cloud for running crews.
- multi-agent
- Python
Open sourcecrewai.comAgent frameworks
Open sourceHaystack
Haystack is an open source framework from deepset for search and question answering. You compose pieces such as retrievers and generators.
- RAG
- search
- Python
Open sourcehaystack.deepset.aiAgent frameworks
Open sourceLangChain
LangChain is a library for building apps on language models. It covers prompts, retrieval, and agents in Python and JavaScript.
- Python
- JavaScript
- RAG
Open sourcelangchain.comAgent frameworks
Open sourceLangGraph
LangGraph is a library for agents that follow a graph of steps, with pauses and retries. It comes from the LangChain team.
- agents
- workflows
- Python
Open sourcelangchain.comAgent frameworks
Open sourceLlamaIndex
LlamaIndex connects documents and data to language models. People use it to build search and question answering over private files.
- RAG
- documents
- Python
Open sourcellamaindex.aiAgent frameworks
Open sourceOpenAI Agents SDK
The OpenAI Agents SDK is a Python library for agents that call tools, hand work to other agents, and check results. It is open source.
- Python
- OpenAI
- tools
Open sourceopenai.github.ioAgent frameworks
Open sourcePydanticAI
PydanticAI is a Python agent framework from the Pydantic team. Type hints describe the tools and the shape of the model's output.
- Python
- structured output
Open sourcepydantic.dev
TypeScript and multi-language kits
Mastra, the Vercel AI SDK, and Agent-Native are TypeScript. Google ADK is Google's open source kit and ships in several languages.
Agent frameworks
Open sourceAgent-Native
Agent-Native is an open source TypeScript framework for building agents that share actions with a user interface. You define a capability once, and the agent, the app, and other clients call the same code.
- TypeScript
- agents
- UI
Open sourceagent-native.comAgent frameworks
Open sourceGoogle ADK
The Agent Development Kit is Google's open source framework for building, evaluating, and deploying agents. It ships in several languages.
- Python
- TypeScript
- Gemini
Open sourceadk.devAgent frameworks
Open sourceMastra
Mastra is a TypeScript framework for agents and workflows. It is meant to live inside a Node or Next.js app.
- TypeScript
- Next.js
- agents
Open sourcemastra.aiAgent frameworks
Open sourceVercel AI SDK
The AI SDK is Vercel's TypeScript toolkit for calling models, streaming text, and building agents. It works with React, Next.js, and other web frameworks.
- TypeScript
- React
- streaming
Open sourceai-sdk.dev
Microsoft's libraries
Start with Microsoft Agent Framework. AutoGen and Semantic Kernel are still listed because the projects remain published.
Agent frameworks
Open sourceAutoGen
AutoGen is Microsoft's multi-agent framework. It is in maintenance mode, so new work is directed to Microsoft Agent Framework, but the library and docs remain published.
- multi-agent
- Python
- Microsoft
Open sourcemicrosoft.github.ioAgent frameworks
Open sourceMicrosoft Agent Framework
Microsoft Agent Framework is Microsoft's current library for building agents in Python and .NET. New projects are pointed here instead of AutoGen or Semantic Kernel.
- Python
- .NET
- Microsoft
Open sourcelearn.microsoft.comAgent frameworks
Open sourceSemantic Kernel
Semantic Kernel is Microsoft's library for connecting models to your own code. It is still published, and Microsoft now points new agent projects to Microsoft Agent Framework.
- Python
- .NET
- Microsoft
Open sourcelearn.microsoft.com
Visual builders, models, and tool access
Dify and Flowise are open source apps with a canvas. Ollama runs models locally. Letta is for agents that keep memory. Composio connects an agent to other apps. Hugging Face hosts models, datasets, and demos.
Agent frameworks
Open sourceComposio
Composio connects an agent to apps such as GitHub, Slack, and Gmail, and handles sign-in for those tools. The SDK is open source, and the hosted service has a free tier.
- tools
- integrations
- auth
Freemiumcomposio.devAgent frameworks
Open sourceDify
Dify is an open source platform for building AI apps and agents with a visual editor. You can self-host it or use Dify Cloud.
- visual builder
- self-hosted
- RAG
Open sourcedify.aiAgent frameworks
Open sourceFlowise
Flowise is an open source visual builder for model workflows. You connect nodes for models, tools, and data, then call the result from an API.
- visual builder
- self-hosted
Open sourceflowiseai.comAgent frameworks
Hugging Face
Hugging Face hosts models, datasets, and Spaces where people demo AI apps. Browsing the hub is free, and many of the libraries around it are open source.
- models
- datasets
- demos
Freemiumhuggingface.coAgent frameworks
Open sourceLetta
Letta, formerly MemGPT, is an open source platform for agents that keep memory over time. You can run it yourself or use the hosted service.
- memory
- agents
- self-hosted
Open sourceletta.comAgent frameworks
Open sourceOllama
Ollama runs open models on your own computer. You pull a model and chat with it, or call it from other tools on localhost.
- local models
- self-hosted
Open sourceollama.com
Categories
Other guides
21 tools in this guide on AgentAtlas. Each card links to the listing, and the listing links to the official site.