RainLoop vs Roundcube
A side-by-side comparison of two self-hosted mail servers options — licensing, setup difficulty, resource needs, and what each one replaces.
Roundcube
Browser-based IMAP webmail client
| Feature | RainLoop | Roundcube |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 15 · At risk | 91 · Excellent |
| Status | Archived | Actively maintained |
| Category | Mail Servers | Mail Servers |
| License | AGPL-3.0 | GPL-3.0 |
| Language | PHP | PHP |
| Setup difficulty | Easy | Easy |
| Min. RAM | 128 MB | 256 MB |
| Deployment | docker, bare-metal, source | docker, bare-metal, source |
| GitHub stars | ★ 4,114 | ★ 7,189 |
| First released | 2013 | 2008 |
| Replaces | Gmail, Outlook Web | Gmail, Outlook Web |
What are RainLoop and Roundcube?
RainLoop
RainLoop is a fast, simple webmail client with a modern interface that works with any IMAP and SMTP server. It stores no email data itself, acting as a thin client.
- Modern, responsive UI
- No database required
- Multi-account support
- Works with any IMAP server
Roundcube
Roundcube is a widely used, browser-based IMAP webmail client with a clean interface and a strong plugin ecosystem. It is commonly bundled with self-hosted mail servers.
- Full-featured IMAP webmail
- Extensive plugin system
- Drag-and-drop interface
- Address book and folder management
RainLoop vs Roundcube: key differences
The biggest difference is maintenance: RainLoop's repository is archived and no longer developed, while Roundcube is actively maintained. Both projects are written in PHP. Licensing differs — AGPL-3.0 for RainLoop versus GPL-3.0 for Roundcube. RainLoop is the lighter option, starting around 128 MB of RAM against 256 MB for Roundcube. Roundcube is the more established project (first released 2008), while RainLoop arrived in 2013.
Why pick each one
Choose RainLoop if…
- Released under the AGPL-3.0 license
- Easy to set up — beginner-friendly
- First-class Docker support for quick deployment
- Active community (4.1k GitHub stars)
Watch out for
- Development largely stalled
- SnappyMail is the active fork
Choose Roundcube if…
- Mature and stable
- Widely supported
Watch out for
- Default UI feels dated
- Webmail only, needs a mail server
Frequently asked questions
Is RainLoop or Roundcube better?
Neither is universally better. Roundcube has the larger community; both share a easy setup difficulty, so the decision comes down to features and licensing.
Are RainLoop and Roundcube free and open-source?
Yes. RainLoop is licensed under AGPL-3.0 and Roundcube under GPL-3.0. Both can be self-hosted at no software cost.
Can I run RainLoop and Roundcube with Docker?
RainLoop: yes. Roundcube: yes.
Which is lighter on resources, RainLoop or Roundcube?
RainLoop has the smaller minimum footprint at 128 MB of RAM, compared to about 256 MB for Roundcube. Real-world usage depends on library size, user count, and enabled features.