Fathom Lite vs PostHog
A side-by-side comparison of two self-hosted web analytics options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | Fathom Lite | PostHog |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 57 · Fair | 99 · Excellent |
| Category | Web Analytics | Web Analytics |
| License | MIT | MIT |
| Language | Go | Python |
| Setup difficulty | Easy | Hard |
| Min. RAM | 128 MB | 4,096 MB |
| Deployment | binary, docker | docker, kubernetes |
| GitHub stars | ★ 8,020 | ★ 39,900 |
| First released | 2018 | 2020 |
| Replaces | Google Analytics | Google Analytics, Mixpanel, Amplitude |
What are Fathom Lite and PostHog?
Fathom Lite
Fathom Lite is the open-source edition of Fathom Analytics, providing simple, privacy-focused website analytics. It targets users who want a lightweight self-hosted analytics tool. It is deployed as a single binary or via Docker.
- Simple privacy-focused analytics
- Single-binary deployment
- No cookies
- Lightweight dashboard
PostHog
PostHog is an open-source product analytics platform with event tracking, session replay, feature flags, and A/B testing. It targets product teams wanting an all-in-one analytics suite. It is deployed via Docker or Kubernetes.
- Product analytics and funnels
- Session replay
- Feature flags and experiments
- Self-hostable all-in-one
Fathom Lite vs PostHog: key differences
Fathom Lite is written in Go, while PostHog is built with Python. Fathom Lite is the lighter option, starting around 128 MB of RAM against 4,096 MB for PostHog. Fathom Lite is the more established project (first released 2018), while PostHog arrived in 2020. PostHog has the considerably larger community, at 39,900 GitHub stars versus 8,020.
Why pick each one
Choose Fathom Lite if…
- Very easy to run
- Privacy-friendly
- Lightweight
Watch out for
- Lite edition no longer actively developed
- Basic feature set
Choose PostHog if…
- Comprehensive product suite
- Session replay included
- Open-core model
Watch out for
- Heavy to self-host
- Self-host edition is scaled down
Frequently asked questions
Is Fathom Lite or PostHog better?
Neither is universally better. PostHog has the larger community, while Fathom Lite is simpler to set up (easy difficulty). Choose based on the comparison table above and your own setup.
Are Fathom Lite and PostHog free and open-source?
Yes. Fathom Lite is licensed under MIT and PostHog under MIT. Both can be self-hosted at no software cost.
Can I run Fathom Lite and PostHog with Docker?
Fathom Lite: yes. PostHog: yes.
Which is lighter on resources, Fathom Lite or PostHog?
Fathom Lite has the smaller minimum footprint at 128 MB of RAM, compared to about 4,096 MB for PostHog. Real-world usage depends on library size, user count, and enabled features.