n8n
The most-starred repo here that isn't open source
What it is
A fair-code workflow automation platform combining visual node-based building with custom code, 400+ integrations, and native AI and agent capabilities, self-hostable or cloud.
Why it's interesting
Enormously popular and constantly described as open source — but n8n itself uses the term 'fair-code', not open source. The Sustainable Use License limits use to your own internal business, non-commercial, or personal purposes, and forbids hosting n8n as a commercial service.
Use cases
- Internal automation and AI agent workflows
- Webhook-driven SaaS integrations
Who it's for
Ops and dev teams automating internal processes
Setup
Easy. npx or Docker one-liner; production wants Postgres and more
Limitations & cautions
The license restricts commercial hosting and redistribution — fine for internal use, disqualifying for the open-source label.
Editorial takeaway
Excellent software, and genuinely generous terms for most users. Just not open source — for an MIT visual builder, see Langflow.