head to head · open source
PostHog vs Fathom Lite
PostHog has 39,865 GitHub stars, 3,404 forks, 5,637 open issues and last shipped today. Fathom Lite has 8,020 stars, 383 forks, 5 open issues and last shipped 6 months ago. PostHog leads on adoption by 397% (39,865 vs 8,020 stars). PostHog is written in Python under a custom or non-standard licence; Fathom Lite is written in Go under MIT. PostHog has attracted 9% as many forks as stars, Fathom Lite 5%. PostHog was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (analytics), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| PostHog | Fathom Lite | |
|---|---|---|
| GitHub stars | ★ 40K | ★ 8.0K |
| License | Custom / other | MIT |
| Written in | Python | Go |
| Last push | 2026-09-20 | 2026-03-18 |
| Forks | ⑂ 3.4K | ⑂ 383 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick PostHog if
- You weight community size — 40K stars and counting
- You want the Custom / other license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick Fathom Lite if
- You want the Fathom Lite feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Go
- You evaluated both and Fathom Lite fits your workflow better
About PostHog
PostHog is an open source platform for building self driving products, combining product analytics, web analytics, session replay, feature flags, experiments, error tracking, logs, surveys, a data warehouse, data pipelines, AI observability, and workflows in a single system, aimed at product, engineering, and growth teams that want to own their product data rather than rent it.
read the full PostHog overview →
About Fathom Lite
Fathom Lite is the original open source, self hosted edition of Fathom Analytics — a simple, privacy focused website analytics tool written in Go with a Preact dashboard, released under the MIT licence for people who want to run their own analytics server rather than buy a hosted service.
read the full Fathom Lite overview →
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Frequently asked questions
Is PostHog or Fathom Lite more popular?
PostHog has 39,865 GitHub stars and Fathom Lite has 8,020. PostHog has the larger community by that measure.
Are PostHog and Fathom Lite free?
Both are open source. PostHog has no licence declared in this registry, and Fathom Lite is licensed under MIT. Both are free to self-host.
What is the difference between PostHog and Fathom Lite?
PostHog is written in Python and Fathom Lite in Go. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, PostHog or Fathom Lite?
Choose PostHog if you want the larger community (39,865 stars) or its Custom / other licence terms. Choose Fathom Lite if its feature set, stack or MIT licence fits better. Both are self-hostable.