FHEM vs Mozilla WebThings Gateway
A side-by-side comparison of two self-hosted home automation options — licensing, setup difficulty, resource needs, and what each one replaces.
FHEM
Perl-based server for home automation tasks
VS
Mozilla WebThings Gateway
Open gateway for the decentralized web of things
| Feature | FHEM | Mozilla WebThings Gateway |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 62 · Good | 81 · Excellent |
| Category | Home Automation | Home Automation |
| License | GPL-2.0 | MPL-2.0 |
| Language | Perl | TypeScript |
| Setup difficulty | Hard | Medium |
| Min. RAM | 256 MB | 512 MB |
| Deployment | docker, bare-metal | bare-metal, docker |
| GitHub stars | ★ 22 | ★ 2,646 |
| First released | 2005 | 2018 |
| Replaces | SmartThings | SmartThings, Google Home |
What are FHEM and Mozilla WebThings Gateway?
FHEM
FHEM is a long-standing, GPL-licensed server for home automation used to control lights, heating, alarms, and many other devices. It supports a vast range of protocols through community modules.
- Vast protocol support
- Community module library
- Lightweight Perl server
- Long-term reliability
Mozilla WebThings Gateway
WebThings Gateway is an open-source gateway for monitoring and controlling smart home devices over the web using open standards. Originating at Mozilla, it now continues as a community project.
- Web of Things standards
- Add-on device support
- Rules engine
- Local web interface
FHEM vs Mozilla WebThings Gateway: key differences
FHEM is written in Perl, while Mozilla WebThings Gateway is built with TypeScript. Licensing differs — GPL-2.0 for FHEM versus MPL-2.0 for Mozilla WebThings Gateway. FHEM is the lighter option, starting around 256 MB of RAM against 512 MB for Mozilla WebThings Gateway. FHEM is the more established project (first released 2005), while Mozilla WebThings Gateway arrived in 2018. Mozilla WebThings Gateway has the considerably larger community, at 2,646 GitHub stars versus 22.
Why pick each one
Choose FHEM if…
- Extremely mature
- Runs on modest hardware
Watch out for
- Dated, technical interface
- Configuration is arcane
Choose Mozilla WebThings Gateway if…
- Open standards-based
- Privacy-focused
Watch out for
- Smaller community after Mozilla
- Fewer integrations than HA
Frequently asked questions
Is FHEM or Mozilla WebThings Gateway better?
Mozilla WebThings Gateway is the stronger all-round pick: it has both the larger community and the simpler medium setup. Consider FHEM if its specific feature set fits your needs better.
Are FHEM and Mozilla WebThings Gateway free and open-source?
Yes. FHEM is licensed under GPL-2.0 and Mozilla WebThings Gateway under MPL-2.0. Both can be self-hosted at no software cost.
Can I run FHEM and Mozilla WebThings Gateway with Docker?
FHEM: yes. Mozilla WebThings Gateway: yes.
Which is lighter on resources, FHEM or Mozilla WebThings Gateway?
FHEM has the smaller minimum footprint at 256 MB of RAM, compared to about 512 MB for Mozilla WebThings Gateway. Real-world usage depends on library size, user count, and enabled features.