# 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 (143k stars), with ruflo and autogen close behind. Rankings shift as projects gain stars and ship commits.

29 open-source records, ranked by maintained GitHub adoption; sponsorship never affects the ranking. Browse on the web: https://agentsearchengine.app/best/open-source-agent-frameworks

## Ranked

1. [langchain](https://agentsearchengine.app/agents/langchain) — The agent engineering platform. · Open source · Framework · 143k★ · Python · MIT · active 1 day ago · best for builders who want composable primitives and the broadest ecosystem of integrations for llm applications
2. [ruflo](https://agentsearchengine.app/agents/ruflo) — The leading agent meta-harness. Deploy intelligent multi-player swarms, coordinate autonomous workflows, and build conversational AI systems. · Open source · Framework · 67k★ · TypeScript · MIT · active 1 day ago · best for adding tools, memory, loops, and sandboxes on top of claude code or codex
3. [autogen](https://agentsearchengine.app/agents/autogen) — A programming framework for agentic AI · Open source · Framework · 60k★ · Python · CC-BY-4.0 · active 3 months ago · best for research-grade multi-agent conversation patterns backed by microsoft
4. [crewAI](https://agentsearchengine.app/agents/crewai) — Framework for orchestrating role-playing, autonomous AI agents. By fostering collaborative intelligence, CrewAI empowers agents to work together seamlessly, tackling complex tasks. · Open source · Framework · 57k★ · Python · MIT · active today · best for orchestrating role-based multi-agent crews in python with an approachable api
5. [pydantic-ai](https://agentsearchengine.app/agents/pydantic-ai) — AI Agent Framework, the Pydantic way · Open source · Framework · 19k★ · Python · MIT · active today · best for python teams that want type-safe agent development with the pydantic philosophy
6. [eliza](https://agentsearchengine.app/agents/eliza) — Open source agentic operating system · Open source · Framework · 19k★ · TypeScript · MIT · active today · best for a local-first agent os running on desktop, mobile, or as a system assistant
7. [SuperAGI](https://agentsearchengine.app/agents/superagi) — <> SuperAGI - A dev-first open source autonomous AI agent framework. Enabling developers to build, manage & run useful autonomous agents quickly and reliably. · Open source · Framework · 18k★ · Python · MIT · active 1 year ago · best for provisioning and running concurrent autonomous agents with extensible tooling
8. [agent-framework](https://agentsearchengine.app/agents/agent-framework) — A framework for building, orchestrating and deploying AI agents and multi-agent workflows with support for Python and.NET. · Open source · Framework · 13k★ · Python · MIT · active today · best for production multi-agent workflows in .net or python with microsoft tooling
9. [hive](https://agentsearchengine.app/agents/hive) — Multi-Agent Harness for Production AI · Open source · Framework · 11k★ · Python · Apache-2.0 · active 2 months ago · best for production agent workloads needing state, failure recovery, and human oversight
10. [evolver](https://agentsearchengine.app/agents/evolver) — The GEP-powered self-evolving engine for AI agents. Auditable evolution with Genes, Capsules, and Events. | evomap.ai · Open source · Framework · 8.9k★ · JavaScript · GPL-3.0 · active 7 days ago
11. [Upsonic](https://agentsearchengine.app/agents/upsonic) — Build autonomous AI agents in Python. · Open source · Framework · 7.9k★ · Python · MIT · active 1 month ago
12. [yao](https://agentsearchengine.app/agents/yao) — Build AI agents and web apps — with a single binary. · Open source · Framework · 7.6k★ · Go · active today
13. [harness-sdk](https://agentsearchengine.app/agents/harness-sdk) — Build an agent harness and control it end-to-end. Open-source SDK for production AI agents in Python & TypeScript - any model, any cloud. · Open source · SDK / library · 6.8k★ · Python · Apache-2.0 · active today
14. [open-multi-agent](https://agentsearchengine.app/agents/open-multi-agent) — TypeScript 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 source · Framework · 6.7k★ · TypeScript · MIT · active 1 day ago
15. [intentkit](https://agentsearchengine.app/agents/intentkit) — IntentKit is an open-source, self-hosted cloud agent cluster that manages a collaborative team of AI agents for you. · Open source · Framework · 6.5k★ · Python · MIT · active 2 days ago
16. [agents](https://agentsearchengine.app/agents/agents) — An Open-source Framework for Data-centric, Self-evolving Autonomous Language Agents · Open source · Framework · 6.0k★ · Python · Apache-2.0 · active 1 year ago
17. [rllm](https://agentsearchengine.app/agents/rllm) — Democratizing Reinforcement Learning for LLMs · Open source · Framework · 5.8k★ · Python · Apache-2.0 · active 3 days ago
18. [agent-governance-toolkit](https://agentsearchengine.app/agents/agent-governance-toolkit) — AI 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 source · SDK / library · 5.6k★ · Python · MIT · active today
19. [ag2](https://agentsearchengine.app/agents/ag2) — AG2 (formerly AutoGen): The Open-Source AgentOS.Join us at: https://discord.gg/sNGSwQME3x · Open source · Framework · 4.8k★ · Python · Apache-2.0 · active today
20. [youtu-agent](https://agentsearchengine.app/agents/youtu-agent) — A simple yet powerful agent framework that delivers with open-source models · Open source · Framework · 4.6k★ · Python · active 4 months ago
21. [fast-agent](https://agentsearchengine.app/agents/fast-agent) — Code, Build and Evaluate agents - excellent Model and Skills/MCP/ACP/A2A Support · Open source · Framework · 3.9k★ · Python · Apache-2.0 · active today
22. [opengap](https://agentsearchengine.app/agents/opengap) — A framework-agnostic, git-native standard for defining AI agents · Open source · Framework · 2.9k★ · TypeScript · MIT · active 1 month ago
23. [Vibe-Skills](https://agentsearchengine.app/agents/vibe-skills) — Vibe-Skills is an all-in-one AI skills package. · Open source · SDK / library · 2.6k★ · Python · Apache-2.0 · active today
24. [harmonist](https://agentsearchengine.app/agents/harmonist) — Portable AI agent orchestration with mechanical protocol enforcement. 186 agents, zero runtime dependencies. · Open source · Framework · 2.4k★ · Python · MIT · active 1 month ago
25. [verl-agent](https://agentsearchengine.app/agents/verl-agent) — verl-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 source · Framework · 2.2k★ · Python · Apache-2.0 · active 1 month ago
26. [yomo](https://agentsearchengine.app/agents/yomo) — Serverless AI Agent Framework with Geo-distributed Edge AI Infra. · Open source · Framework · 1.9k★ · Rust · active 3 days ago
27. [DemoGPT](https://agentsearchengine.app/agents/demogpt) — Create 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 source · Framework · 1.9k★ · Python · MIT · active 4 months ago
28. [Agently](https://agentsearchengine.app/agents/agently) — [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 Flow · Open source · Framework · 1.6k★ · Python · Apache-2.0 · active 3 days ago
29. [flowcraft](https://agentsearchengine.app/agents/flowcraft) — Production-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 source · SDK / library · 484★ · Go · MIT · active today

## FAQ

**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.

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Source: [Agent Search Engine](https://agentsearchengine.app) — https://agentsearchengine.app/best/open-source-agent-frameworks