Open-source · Coding · 16 of 17 tools · updated Oct 17, 2026
Open-source AI tools to build AI agents (frameworks)
Langflow leads the open-source options to build AI agents (frameworks) at 98/100, with 155,764 GitHub stars. 16 of the 17 tools tracked for this job publish their source, so you can read it, fork it or self-host it. It is also the top-ranked tool for this job overall, open-source or not.
Same evidence score as the ranking — GitHub stars, Hacker News mentions, release activity, free access — recomputed nightly, never sold. See all 17 tools to build AI agents (frameworks).
Top 3
evidence / 100
+ Python-native components can be edited inline, so flows are not limited to built-in nodes.
− Several critical security vulnerabilities in 2025 made exposed instances risky.
+ Covers prompt management, knowledge bases, and deployable APIs in one self-hostable app.
− Complex workflows get unwieldy in the visual canvas and version control is weak.
+ Largest integration catalogue of any framework, so almost any provider is one import away.
− Frequent breaking API changes and heavy abstractions make simple things feel over-engineered.
All 16, side by side
| Tool | Score | Stars | Source | Days idle | Platforms |
|---|---|---|---|---|---|
| Langflow | 98 | 155,764 | langflow-ai/langflow | 0 | web, linux, mac, windows |
| Dify | 96 | 158,681 | langgenius/dify | 0 | web, linux |
| LangChain | 96 | 147,959 | langchain-ai/langchain | 0 | cli, api |
| GGoose | 92 | 55,352 | block/goose | 0 | cli, mac, linux, windows |
 AutoGen | 91 | 61,443 | microsoft/autogen | 0 | cli, api |
 CrewAI | 91 | 59,784 | crewAIInc/crewAI | 0 | cli, api |
 LlamaIndex | 90 | 52,534 | run-llama/llama_index | 2 | cli, api |
 LangGraph | 89 | 43,387 | langchain-ai/langgraph | 0 | cli, api |
| OOpenAI Agents SDK | 87 | 30,068 | openai/openai-agents-python | 2 | cli, api |
 Mastra | 87 | 28,862 | mastra-ai/mastra | 0 | cli, api |
 Google Agent Development Kit | 85 | 21,889 | google/adk-python | 0 | cli, api |
 Pydantic AI | 85 | 20,654 | pydantic/pydantic-ai | 0 | cli, api |
 Claude Agent SDK | 80 | 8,291 | anthropics/claude-agent-sdk-python | 0 | cli, api |
 smolagents | 73 | 29,893 | huggingface/smolagents | 10 | cli, api |
 Vercel AI SDK | 72 | 27,359 | vercel/ai | 0 | api, cli |
 Flowise | 42 | 55,509 | FlowiseAI/Flowise | 64 | web, linux |
Open source here means the tool's own source is public, not that a vendor published an SDK. Self-hosting cost is yours.
Head to head: Langflow vs Dify Langflow vs LangChain Dify vs LangChain