Open source · self-hostable
Best open-source agent frameworks
The open-source agent frameworks in the index — self-hostable, inspectable, and free to run. Ranked by real maintained adoption (GitHub stars and recent commit activity), never by sponsorship. Open source buys you control, privacy, and no vendor lock-in; the trade-off is that you host and maintain it yourself. Right now it's led by langchain (147k stars), with ruflo and MetaGPT close behind. Rankings shift as projects gain stars and ship commits.
langchainFrameworkThe agent engineering platform.Open sourcePython · MITVerified · Active 147kGitHub starsrufloFrameworkThe leading agent meta-harness. Deploy intelligent multi-player swarms, coordinate autonomous workflows, and build conversational AI systems.Open sourceTypeScript · MITVerified · Active 73kGitHub starsMetaGPTFrameworkA multi-agent framework that assigns software-company roles to LLM agents to turn a requirement into a project.Open sourcePython · MITVerified 71kGitHub starsautogenFrameworkA programming framework for agentic AI; upstream is in maintenance mode.Open sourcePython · CC-BY-4.0Verified 61kGitHub starscrewAIFrameworkFramework for orchestrating role-playing, autonomous AI agents. By fostering collaborative intelligence, CrewAI empowers agents to work together seamlessly, tackling complex tasks.Open sourcePython · MITVerified · Active 59kGitHub starsLlamaIndexFrameworkFramework for connecting LLMs and agents to your own documents and data.Open sourceMITVerified · Active 52kGitHub starsLangGraphFrameworkLangChain's low-level orchestration framework for stateful, controllable agents.Open sourcePython · MITVerified · Active 42kGitHub starsDSPyFrameworkStanford's framework for programming, not prompting, language models, with optimisers for prompts and weights.Open sourcePython · MITVerified · Active 38kGitHub starsCopilotKitFrameworkThe frontend stack for agents: generative UI, shared state and human-in-the-loop for web, mobile, Slack and Teams.Open sourceTypeScript · MITVerified · Active 38kGitHub starsAgentScopeFrameworkA production-ready Python agent framework built around model reasoning and tool use rather than rigid orchestration.Open sourcePython · Apache-2.0Verified · Active 33kGitHub starsOpenAI Agents SDK (Python)FrameworkOpenAI's lightweight, provider-agnostic Python framework for multi-agent workflows.Open sourcePython · MITVerified · Active 30kGitHub starssmolagentsFrameworkMinimal agent library where agents write their actions as Python code.Open sourceApache-2.0Verified · Active 30kGitHub stars
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Semantic KernelFrameworkMicrosoft's model-agnostic SDK for AI agents in C#, Python and Java, now succeeded by Microsoft Agent Framework.Open sourceC# · MITVerified · Active 29kGitHub starsMastraFrameworkA TypeScript framework for AI applications and agents, with model routing, workflows, RAG and evals.Open sourceTypeScript · Apache-2.0Verified · Active 28kGitHub starsAI SDK (Vercel)FrameworkVercel's provider-agnostic TypeScript toolkit for AI applications and agents in Next.js, React, Svelte, Vue and Node.Open sourceTypeScript · Apache-2.0Verified · Active 27kGitHub starsLetta (formerly MemGPT)FrameworkStateful agents with persistent memory that learn and improve over time, formerly MemGPT.Open sourceApache-2.0Verified · Active 25kGitHub starsAgent Development Kit (Google ADK)FrameworkGoogle's open-source, code-first Python framework for building, evaluating and deploying AI agents.Open sourcePython · Apache-2.0Verified · Active 22kGitHub starspydantic-aiFrameworkAI Agent Framework, the Pydantic wayOpen sourcePython · MITVerified · Active 20kGitHub starselizaFrameworkOpen source agentic operating systemOpen sourceTypeScript · MITVerified · Active 20kGitHub starsCAMELFrameworkAn open-source multi-agent framework from the CAMEL-AI community for studying and building agent societies.Open sourcePython · Apache-2.0Verified · Active 18kGitHub starsSuperAGIFramework<> SuperAGI - A dev-first open source autonomous AI agent framework. Enabling developers to build, manage & run useful autonomous agents quickly and reliably.Open sourcePython · MITVerified 18kGitHub starsagent-frameworkFrameworkA framework for building, orchestrating and deploying AI agents and multi-agent workflows with support for Python and.NET.Open sourcePython · MITVerified · Active 14kGitHub starstxtaiFrameworkAn all-in-one Python framework for semantic search, LLM orchestration and language-model workflows.Open sourcePython · Apache-2.0Verified · Active 13kGitHub starshiveFrameworkMulti-Agent Harness for Production AIOpen sourcePython · Apache-2.0Verified · Active 11kGitHub starsVoltAgentFrameworkAn open-source TypeScript agent framework with a companion console for observability, evals and deployment.Open sourceTypeScript · MITVerified · Active 11kGitHub starsevolverFrameworkThe GEP-powered self-evolving engine for AI agents. Auditable evolution with Genes, Capsules, and Events. | evomap.aiOpen sourceJavaScript · GPL-3.0Verified · Active 9.1kGitHub starsAgent Development Kit for Go (Google ADK)FrameworkGoogle's open-source, code-first Go toolkit for building, evaluating and deploying AI agents.Open sourceGo · Apache-2.0Verified · Active 8.8kGitHub starsmcp-agentFrameworkA composable Python framework for building agents from MCP servers and simple workflow patterns.Open sourcePython · Apache-2.0Verified 8.6kGitHub starsharness-sdkSDK / libraryBuild an agent harness and control it end-to-end. Open-source SDK for production AI agents in Python & TypeScript - any model, any cloud.Open sourcePython · Apache-2.0Verified · Active 8.5kGitHub starsyaoFrameworkBuild AI agents and web apps — with a single binary.Open sourceGoVerified · Active 8.0kGitHub starsUpsonicFrameworkBuild autonomous AI agents in Python.Open sourcePython · MITVerified 8.0kGitHub starsSwarmsFrameworkA Python multi-agent orchestration framework with prebuilt sequential, concurrent and hierarchical architectures.Open sourcePython · Apache-2.0Verified · Active 7.2kGitHub starsopen-multi-agentFrameworkTypeScript multi-agent orchestration framework. Describe a goal, a coordinator decomposes it into a task DAG that runs on any LLM: Claude, ChatGPT, Gemini, DeepSeek, or local models.Open sourceTypeScript · MITVerified · Active 7.0kGitHub starsintentkitFrameworkIntentKit is an open-source, self-hosted cloud agent cluster that manages a collaborative team of AI agents for you.Open sourcePython · MITVerified · Active 6.5kGitHub starsagent-governance-toolkitSDK / libraryAI Agent Governance Toolkit — Policy enforcement, zero-trust identity, execution sandboxing, and reliability engineering for autonomous AI agents. Covers 10/10 OWASP Agentic Top 10.Open sourcePython · MITVerified · Active 6.4kGitHub starsAtomic AgentsFrameworkA lightweight, modular Python framework for building agent pipelines from small, composable pieces.Open sourcePython · MITVerified · Active 6.3kGitHub starsagentsFrameworkAn Open-source Framework for Data-centric, Self-evolving Autonomous Language AgentsOpen sourcePython · Apache-2.0Verified 6.0kGitHub starsrllmFrameworkDemocratizing Reinforcement Learning for LLMsOpen sourcePython · Apache-2.0Verified · Active 5.8kGitHub starsag2FrameworkAG2 (formerly AutoGen): The Open-Source AgentOS.Join us at: https://discord.gg/sNGSwQME3xOpen sourcePython · Apache-2.0Verified · Active 5.0kGitHub starsyoutu-agentFrameworkA simple yet powerful agent framework that delivers with open-source modelsOpen sourcePythonVerified 4.6kGitHub starsKoogFrameworkJetBrains' Kotlin and Java framework for predictable, fault-tolerant AI agents across JVM, Android, iOS and the browser.Open sourceKotlin · Apache-2.0Verified · Active 4.6kGitHub starsLangroidFrameworkA lightweight Python framework for multi-agent LLM applications, from CMU and UW-Madison researchers.Open sourcePython · MITVerified · Active 4.1kGitHub starsfast-agentFrameworkCode, Build and Evaluate agents - excellent Model and Skills/MCP/ACP/A2A SupportOpen sourcePython · Apache-2.0Verified · Active 3.9kGitHub starsOpenAI Agents SDK (TypeScript)FrameworkOpenAI's lightweight, provider-agnostic TypeScript framework for multi-agent workflows and voice agents.Open sourceTypeScript · MITVerified · Active 3.9kGitHub starsVibe-SkillsSDK / libraryVibe-Skills is an all-in-one AI skills package.Open sourcePython · Apache-2.0Verified · Active 3.5kGitHub starsBeeAI FrameworkFrameworkA framework for production-ready multi-agent systems with matching Python and TypeScript libraries.Open sourcePython · Apache-2.0Verified · Active 3.4kGitHub starsopengapFrameworkA framework-agnostic, git-native standard for defining AI agentsOpen sourceTypeScript · MITVerified 3.0kGitHub starsverl-agentFrameworkverl-agent is an extension of veRL, designed for training LLM/VLM agents via RL. verl-agent is also the official code for paper "Group-in-Group Policy Optimization for LLM Agent Training"Open sourcePython · Apache-2.0Verified 2.3kGitHub starsharmonistFrameworkPortable AI agent orchestration with mechanical protocol enforcement. 186 agents, zero runtime dependencies.Open sourcePython · MITVerified 2.3kGitHub starsyomoFrameworkServerless AI Agent Framework with Geo-distributed Edge AI Infra.Open sourceRustVerified · Active 1.9kGitHub starsDemoGPTFrameworkCreate LLM agents in a second with your prompts. Everything you need to create an LLM Agent - tools, prompts, frameworks, and models - all in one place.Open sourcePython · MITVerified 1.9kGitHub starsAgentlyFramework[GenAI Application Development Framework] Build GenAI application quick and easy Easy to interact with GenAI agent in code using structure data and chained-calls syntax Use Event-Driven FlowOpen sourcePython · Apache-2.0Verified · Active 1.7kGitHub starsflowcraftSDK / libraryProduction-grade Go SDK for building AI agents with long-term memory, knowledge retrieval, and voice — runnable as a library, a daemon, or a real-time pipeline.Open sourceGo · MITVerified · Active 416GitHub starsCybaraFrameworkSelf-hosted, open-source AI agent operating system with multi-agent orchestration and MCP.Open sourceTypeScript · MITVerified · Active 31GitHub stars
Frequently asked
- What are the best open-source agent frameworks?
- The projects listed below, ranked by maintained adoption — GitHub stars plus recent activity — so you see what's genuinely used and still maintained, not abandoned.
- Are open-source agent frameworks free?
- The software is free to run and self-host. You still pay for the infrastructure you run it on and any model or API usage it makes.
- Open-source or commercial agent frameworks — which should I choose?
- Pick open source for control, privacy, and no lock-in when you're happy to host and maintain it; pick a commercial product for a managed, supported experience. You can compare both in the full agent frameworks category.