n8n

n8n is a visual workflow automation platform that has aggressively repositioned itself as an AI-agent orchestration tool. You drag nodes onto a canvas to wire 500+ integrations together, drop in JavaScript or Python where the UI runs out, and chain LLM calls into multi-step agents with branching, memory, RAG retrieval, and human-in-the-loop checkpoints. Unlike pure agent SDKs, it gives you the plumbing (cron triggers, webhooks, queues, retries, credential vault) that production automations actually need.

It's a serious alternative to Zapier or Make for engineering teams, and a more pragmatic alternative to LangChain for ops/automation work where you want a UI plus code escape hatches. The code is Fair-Code licensed (source-available, free to self-host but commercial restrictions apply), with a paid Cloud plan and an Enterprise tier that adds SSO, RBAC, audit logs, and external secret stores. The GitHub repo sits at ~194k stars, which is one of the largest communities in the automation space.

It's model-agnostic: OpenAI, Anthropic, Google, Mistral, Ollama, local models, vector stores (Pinecone, Qdrant, Weaviate, Supabase pgvector), and MCP servers are all first-class nodes. The main caveats are that the Fair-Code license isn't OSI-approved, the agent nodes still feel newer than the core automation features, and complex agent debugging can get unwieldy on large canvases.