Courier Mail Server vs WildDuck
A side-by-side comparison of two self-hosted mail servers options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | Courier Mail Server | WildDuck |
|---|---|---|
| Deploy effort | Read-the-docs project | Under-an-hour setup |
| Health score | 62 · Good | 86 · Excellent |
| Category | Mail Servers | Mail Servers |
| License | GPL-3.0 | EUPL-1.2 |
| Language | C | JavaScript |
| Setup difficulty | Hard | Hard |
| Min. RAM | 512 MB | 1,024 MB |
| Deployment | bare-metal, source | docker, bare-metal |
| GitHub stars | ★ 13 | ★ 2,108 |
| First released | 2000 | 2017 |
| Replaces | Microsoft Exchange | Microsoft Exchange, Gmail |
What are Courier Mail Server and WildDuck?
Courier Mail Server
Courier is an integrated mail server suite that combines an MTA with IMAP, POP3, ESMTP, and webmail components. It provides a complete mail system from a single coordinated project.
- Integrated MTA and IMAP
- Built-in webmail
- Maildir storage
- LDAP authentication
WildDuck
WildDuck is a modern, scalable mail server providing IMAP, POP3, and a full REST API for managing mailboxes. It stores messages in MongoDB and is designed for clustered, highly available deployments.
- IMAP and POP3
- Full REST API
- MongoDB storage
- Designed for scale
Courier Mail Server vs WildDuck: key differences
Courier Mail Server is written in C, while WildDuck is built with JavaScript. Licensing differs — GPL-3.0 for Courier Mail Server versus EUPL-1.2 for WildDuck. Courier Mail Server is the lighter option, starting around 512 MB of RAM against 1,024 MB for WildDuck. Courier Mail Server is the more established project (first released 2000), while WildDuck arrived in 2017. WildDuck has the considerably larger community, at 2,108 GitHub stars versus 13. WildDuck lists first-class Docker deployment; Courier Mail Server does not.
Why pick each one
Choose Courier Mail Server if…
- Released under the GPL-3.0 license
- Written in C
- Lightweight — runs in 512 MB RAM
Choose WildDuck if…
- API-driven management
- Horizontally scalable
Watch out for
- Requires MongoDB
- Complex to operate
Frequently asked questions
Is Courier Mail Server or WildDuck better?
Neither is universally better. WildDuck has the larger community; both share a hard setup difficulty, so the decision comes down to features and licensing.
Are Courier Mail Server and WildDuck free and open-source?
Yes. Courier Mail Server is licensed under GPL-3.0 and WildDuck under EUPL-1.2. Both can be self-hosted at no software cost.
Can I run Courier Mail Server and WildDuck with Docker?
Courier Mail Server: check the project docs for container support. WildDuck: yes.
Which is lighter on resources, Courier Mail Server or WildDuck?
Courier Mail Server has the smaller minimum footprint at 512 MB of RAM, compared to about 1,024 MB for WildDuck. Real-world usage depends on library size, user count, and enabled features.