Cup vs Diun
A side-by-side comparison of two self-hosted automation & workflows options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | Cup | Diun |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 74 · Good | 89 · Excellent |
| Category | Automation & Workflows | Automation & Workflows |
| License | MIT | MIT |
| Language | Rust | Go |
| Setup difficulty | Easy | Easy |
| Min. RAM | 64 MB | 64 MB |
| Deployment | docker, binary | docker, binary |
| GitHub stars | ★ 1,345 | ★ 4,934 |
| First released | 2024 | 2019 |
| Replaces | Watchtower | Watchtower |
What are Cup and Diun?
Cup
Cup is a lightweight tool written in Rust that checks your Docker containers for available image updates. It offers a CLI, a web dashboard, and a JSON API for integration with monitoring systems.
- Fast update checks
- Web dashboard and CLI
- JSON API
- Very low resource use
Diun
Diun is a small utility that watches Docker images in registries and sends a notification when a new version becomes available, without applying updates itself. It lets administrators decide when to upgrade.
- Watches registry images
- Many notification channels
- No automatic updates
- Provider-based discovery
Cup vs Diun: key differences
Cup is written in Rust, while Diun is built with Go. Diun is the more established project (first released 2019), while Cup arrived in 2024. Diun has the considerably larger community, at 4,934 GitHub stars versus 1,345.
Why pick each one
Choose Cup if…
- Released under the MIT license
- Easy to set up — beginner-friendly
- First-class Docker support for quick deployment
- Active community (1.3k GitHub stars)
Choose Diun if…
- Stays in control of upgrades
- Lightweight
Watch out for
- Notifies but does not update
- Configuration needed per source
Frequently asked questions
Is Cup or Diun better?
Neither is universally better. Diun has the larger community; both share a easy setup difficulty, so the decision comes down to features and licensing.
Are Cup and Diun free and open-source?
Yes. Cup is licensed under MIT and Diun under MIT. Both can be self-hosted at no software cost.
Can I run Cup and Diun with Docker?
Cup: yes. Diun: yes.