Nullmailer vs DragonFly Mail Agent
A side-by-side comparison of two self-hosted mail servers options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | Nullmailer | DragonFly Mail Agent |
|---|---|---|
| Deploy effort | Read-the-docs project | Read-the-docs project |
| Health score | 8 · At risk | 71 · Good |
| Category | Mail Servers | Mail Servers |
| License | GPL-2.0 | BSD-3-Clause |
| Language | C++ | C |
| Setup difficulty | Easy | Easy |
| Min. RAM | 16 MB | 32 MB |
| Deployment | bare-metal, source | binary, source |
| GitHub stars | ★ 199 | ★ 265 |
| First released | 2000 | 2008 |
| Replaces | Sendmail | Sendmail, Postfix |
What are Nullmailer and DragonFly Mail Agent?
Nullmailer
Nullmailer is a minimal mail transfer agent designed only to relay outgoing mail to a smart host. It is ideal for servers and workstations that need to send notifications without running a full MTA.
- Relay-only operation
- Tiny footprint
- Smart host forwarding
- Queue management
DragonFly Mail Agent
DragonFly Mail Agent (dma) is a small mail transport agent that accepts mail from the local system and either delivers it locally or forwards it to a smarthost. It is designed for systems that do not need a full MTA.
- Tiny mail transport agent
- Smarthost forwarding
- Local delivery
- Minimal footprint
Nullmailer vs DragonFly Mail Agent: key differences
Nullmailer is written in C++, while DragonFly Mail Agent is built with C. Licensing differs — GPL-2.0 for Nullmailer versus BSD-3-Clause for DragonFly Mail Agent. Nullmailer is the lighter option, starting around 16 MB of RAM against 32 MB for DragonFly Mail Agent. Nullmailer is the more established project (first released 2000), while DragonFly Mail Agent arrived in 2008.
Why pick each one
Choose Nullmailer if…
- Extremely lightweight
- Simple configuration
Watch out for
- Cannot receive mail
- No local delivery
Choose DragonFly Mail Agent if…
- Released under the BSD-3-Clause license
- Easy to set up — beginner-friendly
- Written in C
- Tiny footprint — runs in 32 MB RAM
Frequently asked questions
Is Nullmailer or DragonFly Mail Agent better?
Neither is universally better. DragonFly Mail Agent has the larger community; both share a easy setup difficulty, so the decision comes down to features and licensing.
Are Nullmailer and DragonFly Mail Agent free and open-source?
Yes. Nullmailer is licensed under GPL-2.0 and DragonFly Mail Agent under BSD-3-Clause. Both can be self-hosted at no software cost.
Can I run Nullmailer and DragonFly Mail Agent with Docker?
Nullmailer: check the project docs for container support. DragonFly Mail Agent: check the project docs for container support.
Which is lighter on resources, Nullmailer or DragonFly Mail Agent?
Nullmailer has the smaller minimum footprint at 16 MB of RAM, compared to about 32 MB for DragonFly Mail Agent. Real-world usage depends on library size, user count, and enabled features.