fdm vs mpop
A side-by-side comparison of two self-hosted mail servers options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | fdm | mpop |
|---|---|---|
| Deploy effort | Read-the-docs project | Read-the-docs project |
| Health score | 8 · At risk | 59 · Fair |
| Category | Mail Servers | Mail Servers |
| License | ISC | GPL-3.0 |
| Language | C | C |
| Setup difficulty | Medium | Easy |
| Min. RAM | 32 MB | 16 MB |
| Deployment | binary, source | binary, source |
| GitHub stars | ★ 284 | ★ 19 |
| First released | 2006 | 2005 |
| Replaces | fetchmail, procmail | fetchmail |
What are fdm and mpop?
fdm
fdm is a program that fetches mail from POP3 and IMAP servers and filters it into local mailboxes based on user-defined rules. It combines retrieval and delivery in one lightweight tool.
- Fetches POP3 and IMAP mail
- Rule-based filtering
- Combined fetch and deliver
- Lightweight
mpop
mpop is a small, fast and configurable POP3 client that downloads mail and delivers it to a local mailbox or mail filter. It is often paired with msmtp on self-hosted mail setups.
- Lightweight POP3 retrieval client
- Delivers to local mailbox
- Pairs well with msmtp
fdm vs mpop: key differences
Both projects are written in C. Licensing differs — ISC for fdm versus GPL-3.0 for mpop. Mpop is the lighter option, starting around 16 MB of RAM against 32 MB for fdm. Fdm has the considerably larger community, at 284 GitHub stars versus 19.
Why pick each one
Choose fdm if…
- Released under the ISC license
- Written in C
- Tiny footprint — runs in 32 MB RAM
Choose mpop if…
- Released under the GPL-3.0 license
- Easy to set up — beginner-friendly
- Written in C
- Tiny footprint — runs in 16 MB RAM
Frequently asked questions
Is fdm or mpop better?
Neither is universally better. fdm has the larger community, while mpop is simpler to set up (easy difficulty). Choose based on the comparison table above and your own setup.
Are fdm and mpop free and open-source?
Yes. fdm is licensed under ISC and mpop under GPL-3.0. Both can be self-hosted at no software cost.
Can I run fdm and mpop with Docker?
fdm: check the project docs for container support. mpop: check the project docs for container support.
Which is lighter on resources, fdm or mpop?
mpop has the smaller minimum footprint at 16 MB of RAM, compared to about 32 MB for fdm. Real-world usage depends on library size, user count, and enabled features.