MailCatcher vs Mailpit
A side-by-side comparison of two self-hosted mail servers options — licensing, setup difficulty, resource needs, and what each one replaces.
Mailpit
Email and SMTP testing tool with web UI
| Feature | MailCatcher | Mailpit |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 72 · Good | 93 · Excellent |
| Category | Mail Servers | Mail Servers |
| License | MIT | MIT |
| Language | Ruby | Go |
| Setup difficulty | Easy | Easy |
| Min. RAM | 128 MB | 64 MB |
| Deployment | docker, binary, source | docker, binary |
| GitHub stars | ★ 6,780 | ★ 10,426 |
| First released | 2010 | 2022 |
| Replaces | Mailtrap | Mailtrap, MailHog |
What are MailCatcher and Mailpit?
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
Mailpit
Mailpit is a self-hosted email testing tool that acts as an SMTP server and captures all messages for inspection in a clean web interface. Developers use it to preview and debug application email locally.
- SMTP capture server
- Web message viewer
- REST API
- HTML and link checks
MailCatcher vs Mailpit: key differences
MailCatcher is written in Ruby, while Mailpit is built with Go. Mailpit is the lighter option, starting around 64 MB of RAM against 128 MB for MailCatcher. MailCatcher is the more established project (first released 2010), while Mailpit arrived in 2022.
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 Mailpit if…
- Very fast and small
- Great developer UX
Watch out for
- For testing not production
- Not a real mail server
Frequently asked questions
Is MailCatcher or Mailpit better?
Neither is universally better. Mailpit has the larger community; both share a easy setup difficulty, so the decision comes down to features and licensing.
Are MailCatcher and Mailpit free and open-source?
Yes. MailCatcher is licensed under MIT and Mailpit under MIT. Both can be self-hosted at no software cost.
Can I run MailCatcher and Mailpit with Docker?
MailCatcher: yes. Mailpit: yes.
Which is lighter on resources, MailCatcher or Mailpit?
Mailpit has the smaller minimum footprint at 64 MB of RAM, compared to about 128 MB for MailCatcher. Real-world usage depends on library size, user count, and enabled features.