"Open-source workflow automation" covers very different tools. Some connect SaaS apps with triggers and actions. Some orchestrate data pipelines. Some run long-lived business processes in code. What they share is that you can run them on your own servers, which is usually the point: data stays inside your network and there is no per-task bill.
Below are seven options: six open-source or source-available engines, plus one self-hosted commercial option for business workflows, with the point where each one stops. For hosted tools, see the best no-code workflow automation tools.
The seven options at a glance
| Option | License | Best for |
|---|---|---|
| Jet Admin | Commercial, not open source; self-hosted on Enterprise | Business workflows with apps and approvals on your data |
| n8n | Fair-code (Sustainable Use License) | Integration workflows and AI agents |
| Activepieces | MIT community edition | Zapier-style automations, self-hosted |
| Windmill | AGPL community edition | Scripts, flows and internal apps for developers |
| Node-RED | Apache 2.0 | IoT and event-driven flows |
| Apache Airflow | Apache 2.0 | Scheduled data pipelines |
| Temporal | MIT | Durable workflows in application code |
Business workflows with a UI
1. Jet Admin
Jet Admin is not open source. It is here because many teams looking for self-hosted automation need more than triggers and actions: a request form, an approval queue, a screen where finance or ops can see what is waiting, all on data in their own databases. Jet builds those workflows and the apps around them on 200+ integrations, and workflows and users are unlimited on every plan. On the Enterprise plan it runs on-premise with self-hosted AI models, inside your network.
Granular permissions, SSO and audit logs are on the Business plan and above.
Where it stops: you cannot modify the platform source, and it is not a data pipeline orchestrator.
Integration automation
2. n8n
n8n is a visual workflow builder with hundreds of integrations, code nodes and AI agent nodes, and it can be self-hosted.
Where it stops: its Sustainable Use License is fair-code rather than OSI open source, which limits some commercial uses; business users usually need a builder to set it up.
3. Activepieces
Activepieces offers Zapier-style automations with a friendly builder and an MIT-licensed community edition.
Where it stops: fewer integrations and enterprise features than older platforms.
Developer orchestration
4. Windmill
Windmill turns scripts in Python, TypeScript, Go and more into flows, schedules and simple internal apps.
Where it stops: built for developers who write code.
5. Node-RED
Node-RED wires together devices, APIs and services in a browser-based flow editor, popular in IoT.
Where it stops: less suited to business approvals and user-facing workflows.
6. Apache Airflow
Airflow schedules and monitors data pipelines defined as Python DAGs.
Where it stops: built for batch data work, not human-in-the-loop business processes.
7. Temporal
Temporal runs durable, long-running workflows in application code, with retries and state handled for you.
Where it stops: an engineering tool; there is no business-user interface.
Which to use
- You need self-hosted business workflows with forms, approvals and dashboards: Jet Admin.
- You want self-hosted integration automation: n8n or Activepieces.
- Developers want scripts turned into workflows: Windmill.
- You are wiring devices and events: Node-RED.
- You run data pipelines: Airflow.
- You are building durable workflows into your product: Temporal.
Frequently asked questions
Is n8n open source?
n8n uses a fair-code license: the source is available and self-hosting is free for internal use, but it is not an OSI-approved open-source license.
Why self-host workflow automation?
To keep data inside your network, avoid per-task pricing and control upgrades. The cost is running and securing the service yourself.
Can workflow automation include human approvals?
Some tools support pauses for approval; business workflow tools add the forms and queues people use to approve.
Automate the process, not just the plumbing
Start with Jet Admin for free and build a workflow with the approvals and screens your team needs.