AI Framework/Library

AutoGen

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Open-source multi-agent framework (Python/.NET) with AgentChat and Studio

AutoGen is Microsoft's open-source framework for building agentic applications with your own model API keys. The current stable release (python v0.7.5, Sep 30 2025) ships a layered architecture: Core for event-driven message passing across Python and .NET runtimes, AgentChat for common multi-agent patterns, Extensions for model/tool connectors (OpenAI and Azure OpenAI, Anthropic, Gemini via OpenAI-compatible endpoints, and local models via Ollama), plus AutoGen Studio for no-code multi-agent prototyping and AutoGen Bench for evaluation. It's MIT-licensed and maintained in the open on GitHub.

CrewAI

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MIT-licensed agents, crews, and flows framework with optional control plane

CrewAI is an MIT-licensed Python framework for multi-agent automations. The 1.6.1 release (Nov 29 2025) ships Crews for autonomous collaboration and Flows for event-driven orchestration with guardrails, memory, knowledge, and observability hooks. It runs with your own model/API keys (OpenAI/Azure OpenAI, Anthropic, OpenAI-compatible providers like Groq, or local via Ollama/LM Studio) and offers an optional Crew Control Plane for hosted/on-prem tracing, triggers, and RBAC.

LangChain & LangGraph

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LangChain for LLM apps; LangGraph for stateful graph agents

LangChain provides provider-agnostic LLM tooling, while LangGraph adds a graph-based runtime for controllable, stateful agents with human-in-the-loop, persistence, and streaming. Both are open source with Python/JS SDKs and a growing ecosystem of integrations and middleware.

LangChain

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Open-source framework for LLM apps with LangSmith observability

LangChain is an open-source framework for building LLM apps with composable chains, agents, tools, and RAG. It supports Python and TypeScript, integrates with major model providers and vector stores, and pairs with LangSmith for tracing, monitoring, and evals.

LangGraph

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Graph-based framework for controllable, stateful AI agents

LangGraph is an open-source framework in the LangChain ecosystem for building stateful, multi-step agents with controllable graphs (single, multi-agent, hierarchical flows). It supports human-in-the-loop interrupts, streaming, memory, and tool use, and can be deployed via LangGraph Platform or self-hosted OSS.

Vercel AI SDK

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Open-source TypeScript toolkit for streaming LLM apps with providers, tools, and generative UI

Vercel AI SDK (v6 beta) is a free, open-source toolkit for building streaming AI apps across Next.js, React, Vue/Nuxt, SvelteKit, and Node/Edge runtimes. It provides a unified provider API, tool calling, structured outputs (`generateObject`), server actions/RSC hooks, and generative UI helpers like `streamUI`, with adapters for OpenAI, Anthropic, Google, Mistral, Ollama, and more.