MailCatcher vs swaks
A side-by-side comparison of two self-hosted mail servers options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | MailCatcher | swaks |
|---|---|---|
| Deploy effort | Under-an-hour setup | Read-the-docs project |
| Health score | 72 · Good | 15 · At risk |
| Category | Mail Servers | Mail Servers |
| License | MIT | GPL-2.0 |
| Language | Ruby | Perl |
| Setup difficulty | Easy | Easy |
| Min. RAM | 128 MB | 16 MB |
| Deployment | docker, binary, source | binary, source |
| GitHub stars | ★ 6,780 | ★ 1,344 |
| First released | 2010 | 2003 |
| Replaces | Mailtrap | Mailtrap |
What are MailCatcher and swaks?
MailCatcher
MailCatcher runs a simple SMTP server that catches any message sent to it and displays it in a web interface for developers. It is a development tool for inspecting outgoing email without delivering it.
- Catch-all SMTP server
- Web UI for inspecting mail
- View HTML and plain text
- Developer testing tool
swaks
swaks is a flexible command-line SMTP transaction tester used to diagnose and verify self-hosted mail servers. It can craft and send test messages with fine control over the SMTP conversation.
- Command-line SMTP tester
- Fine control over SMTP transactions
- Diagnoses mail server issues
MailCatcher vs swaks: key differences
MailCatcher is written in Ruby, while swaks is built with Perl. Licensing differs — MIT for MailCatcher versus GPL-2.0 for swaks. Swaks is the lighter option, starting around 16 MB of RAM against 128 MB for MailCatcher. Swaks is the more established project (first released 2003), while MailCatcher arrived in 2010. MailCatcher has the considerably larger community, at 6,780 GitHub stars versus 1,344. MailCatcher lists first-class Docker deployment; swaks does not.
Why pick each one
Choose MailCatcher if…
- Released under the MIT license
- Easy to set up — beginner-friendly
- First-class Docker support for quick deployment
- Mature project with 6.8k GitHub stars
Choose swaks if…
- Released under the GPL-2.0 license
- Easy to set up — beginner-friendly
- Active community (1.3k GitHub stars)
- Written in Perl
Frequently asked questions
Is MailCatcher or swaks better?
Neither is universally better. MailCatcher has the larger community; both share a easy setup difficulty, so the decision comes down to features and licensing.
Are MailCatcher and swaks free and open-source?
Yes. MailCatcher is licensed under MIT and swaks under GPL-2.0. Both can be self-hosted at no software cost.
Can I run MailCatcher and swaks with Docker?
MailCatcher: yes. swaks: check the project docs for container support.
Which is lighter on resources, MailCatcher or swaks?
swaks has the smaller minimum footprint at 16 MB of RAM, compared to about 128 MB for MailCatcher. Real-world usage depends on library size, user count, and enabled features.