Cal.com
Windmill
| Feature | Cal.com | Windmill |
|---|---|---|
| Pricing | Free / from $12/mo | Free / from $10/mo |
| Free Plan | ✓ Yes | ✓ Yes |
| Rating | 4.4 / 5 | 4.4 / 5 |
| Best For | developers, startups, agencies, privacy-conscious-teams | developers, devops-teams, internal-tools, data-pipelines |
| Founded | 2021 | 2022 |
| Scheduling | ✓ | ✓ |
| Self Hosting | ✓ | ✗ |
| Api | ✓ | ✗ |
| Webhooks | ✓ | ✗ |
| Round Robin | ✓ | ✗ |
| Collective Scheduling | ✓ | ✗ |
| Embed | ✓ | ✗ |
| Workflow Editor | ✗ | ✓ |
| Script To Ui | ✗ | ✓ |
| Approval Flows | ✗ | ✓ |
| Multi Language | ✗ | ✓ |
| Self Hostable | ✗ | ✓ |
| Audit Logs | ✗ | ✓ |
✓ Cal.com Pros
- Open-source and self-hostable
- Unlimited event types on free plan
- Full API and webhook access
- White-label and embed options
✗ Cal.com Cons
- Self-hosting requires technical setup
- Fewer integrations than Calendly
- UI less polished than Calendly
✓ Windmill Pros
- Open-source and self-hostable
- Supports Python, TypeScript, Go, Bash, SQL natively
- Auto-generates UI from script parameters
- Excellent scheduling and workflow orchestration
✗ Windmill Cons
- Smaller community than Zapier/n8n
- Self-hosting requires infrastructure knowledge
- Less polished documentation for beginners
The Verdict
Cal.com is built for developers and startups, with a focus on scheduling and self-hosting. Windmill targets developers and devops teams and leads with workflow-editor and script-to-ui.
Pricing is close: Windmill starts at $10/mo versus $12/mo for Cal.com — not a deciding factor on its own.
Both offer free plans, so you can test each with your real workflow before committing to a subscription.
Both tools are a solid fit for developers — in those cases, the decision often comes down to workflow style and how your team prefers to organize work.
This is a genuinely close comparison. If you can, sign up for both free trials (where available) and run a one-week test with your actual team tasks before deciding.