StackStorm vs Windmill
A side-by-side comparison of two self-hosted automation & workflows options — licensing, setup difficulty, resource needs, and what each one replaces.
Windmill
Developer platform for scripts, flows and apps
| Feature | StackStorm | Windmill |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 86 · Excellent | 95 · Excellent |
| Category | Automation & Workflows | Automation & Workflows |
| License | Apache-2.0 | AGPL-3.0 |
| Language | Python | Rust |
| Setup difficulty | Hard | Medium |
| Min. RAM | 2,048 MB | 1,024 MB |
| Deployment | docker, kubernetes, bare-metal | docker, kubernetes |
| GitHub stars | ★ 6,539 | ★ 18,022 |
| First released | 2014 | 2022 |
| Replaces | Zapier, AWS Systems Manager | Zapier, Retool |
What are StackStorm and Windmill?
StackStorm
StackStorm is an event-driven automation platform that connects triggers to actions through rules and workflows. It is commonly used for auto-remediation, security responses and continuous deployment.
- Event-driven rules and triggers
- Large pack ecosystem for integrations
- Workflow engine for complex automation
- ChatOps integration
Windmill
Windmill is a developer platform that turns scripts into workflows, APIs, and internal apps with scheduling and approvals. It targets engineers automating internal tooling. It is deployed via Docker with PostgreSQL.
- Scripts in Python, TypeScript and more
- Auto-generated UIs for scripts
- Flows with branching and retries
- Fast Rust execution engine
StackStorm vs Windmill: key differences
StackStorm is written in Python, while Windmill is built with Rust. Licensing differs — Apache-2.0 for StackStorm versus AGPL-3.0 for Windmill. Windmill is the lighter option, starting around 1,024 MB of RAM against 2,048 MB for StackStorm. StackStorm is the more established project (first released 2014), while Windmill arrived in 2022. Windmill has the considerably larger community, at 18,022 GitHub stars versus 6,539.
Why pick each one
Choose StackStorm if…
- Powerful for ops automation
- Extensive integration packs
Watch out for
- Heavy multi-component install
Choose Windmill if…
- Great for developer automation
- Fast and scalable
- Code-first approach
Watch out for
- More technical than no-code tools
- Requires Postgres
Frequently asked questions
Is StackStorm or Windmill better?
Windmill is the stronger all-round pick: it has both the larger community and the simpler medium setup. Consider StackStorm if its specific feature set fits your needs better.
Are StackStorm and Windmill free and open-source?
Yes. StackStorm is licensed under Apache-2.0 and Windmill under AGPL-3.0. Both can be self-hosted at no software cost.
Can I run StackStorm and Windmill with Docker?
StackStorm: yes. Windmill: yes.
Which is lighter on resources, StackStorm or Windmill?
Windmill has the smaller minimum footprint at 1,024 MB of RAM, compared to about 2,048 MB for StackStorm. Real-world usage depends on library size, user count, and enabled features.