Cuttlefish vs Postal
A side-by-side comparison of two self-hosted mail servers options — licensing, setup difficulty, resource needs, and what each one replaces.
Postal
Complete mail delivery platform for outgoing email
| Feature | Cuttlefish | Postal |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 19 · At risk | 94 · Excellent |
| Category | Mail Servers | Mail Servers |
| License | AGPL-3.0 | MIT |
| Language | Ruby | Ruby |
| Setup difficulty | Medium | Hard |
| Min. RAM | 1,024 MB | 2,048 MB |
| Deployment | docker, bare-metal, source | docker, bare-metal |
| GitHub stars | ★ 1,623 | ★ 16,824 |
| First released | 2014 | 2017 |
| Replaces | Mailgun, SendGrid, Postmark | SendGrid, Mailgun, Postmark |
What are Cuttlefish and Postal?
Cuttlefish
Cuttlefish is a self-hosted transactional email server that sends application email and tracks deliveries, opens, and clicks. It provides a dashboard for monitoring email performance.
- Transactional email delivery
- Open and click tracking
- Delivery monitoring dashboard
- SMTP relay interface
Postal
Postal is a full-featured, self-hosted mail server designed for sending and receiving email for websites and applications. It is a self-hosted alternative to transactional email services.
- Transactional email sending
- Detailed delivery analytics
- HTTP API and webhooks
- Multi-organization support
Cuttlefish vs Postal: key differences
Both projects are written in Ruby. Licensing differs — AGPL-3.0 for Cuttlefish versus MIT for Postal. Cuttlefish is the lighter option, starting around 1,024 MB of RAM against 2,048 MB for Postal. Cuttlefish is the more established project (first released 2014), while Postal arrived in 2017. Postal has the considerably larger community, at 16,824 GitHub stars versus 1,623.
Why pick each one
Choose Cuttlefish if…
- Released under the AGPL-3.0 license
- First-class Docker support for quick deployment
- Active community (1.6k GitHub stars)
- Written in Ruby
Watch out for
- Outbound mail only
- Slower development
Choose Postal if…
- Great for application email
- Strong API
Watch out for
- Multi-component deployment
- Needs careful IP reputation management
Frequently asked questions
Is Cuttlefish or Postal better?
Neither is universally better. Postal has the larger community, while Cuttlefish is simpler to set up (medium difficulty). Choose based on the comparison table above and your own setup.
Are Cuttlefish and Postal free and open-source?
Yes. Cuttlefish is licensed under AGPL-3.0 and Postal under MIT. Both can be self-hosted at no software cost.
Can I run Cuttlefish and Postal with Docker?
Cuttlefish: yes. Postal: yes.
Which is lighter on resources, Cuttlefish or Postal?
Cuttlefish has the smaller minimum footprint at 1,024 MB of RAM, compared to about 2,048 MB for Postal. Real-world usage depends on library size, user count, and enabled features.