MailCatcher vs smtp4dev
A side-by-side comparison of two self-hosted mail servers options — licensing, setup difficulty, resource needs, and what each one replaces.
Not the right match-up?
MailCatcher
Catch-all SMTP server for inspecting test email
VS
smtp4dev
Fake SMTP server for development email testing
| Feature | MailCatcher | smtp4dev |
|---|---|---|
| Category | Mail Servers | Mail Servers |
| License | MIT | GPL-3.0 |
| Language | Ruby | C# |
| Setup difficulty | Easy | Easy |
| Min. RAM | 128 MB | 128 MB |
| Deployment | docker, binary, source | docker, binary |
| GitHub stars | ★ 6,774 | ★ 3,941 |
| First released | 2010 | 2015 |
| Replaces | Mailtrap | Mailtrap |
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
Frequently asked questions
Is MailCatcher or smtp4dev 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 smtp4dev free and open-source?
Yes. MailCatcher is licensed under MIT and smtp4dev under GPL-3.0. Both can be self-hosted at no software cost.
Can I run MailCatcher and smtp4dev with Docker?
MailCatcher: yes. smtp4dev: yes.